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<body>
<div class="head">
<p>
<a href="http://www.w3.org/">
<img width="72" height="48" src="http://www.w3.org/Icons/w3c_home" alt="W3C" />
</a>
</p>
<h1 class="title" id="title">
JSON-LD
API
1.0
</h1>
<h2 id="subtitle">
An
Application
Programming
Interface
for
the
JSON-LD
Syntax
</h2>
<del class="diff-old">Final
Community
Group
Specification
26
June
</del>
<h2 id="w3c-working-draft-12-july-2012">
<acronym title="World Wide Web Consortium">
<ins class="diff-chg">W3C
</ins></acronym><ins class="diff-chg">
Working
Draft
12
July
</ins>
2012
</h2>
<dl>
<dt>
<ins class="diff-new">This
version:
</ins></dt><dd><a href="http://www.w3.org/TR/2012/WD-json-ld-api-20120712/"><ins class="diff-new">
http://www.w3.org/TR/2012/WD-json-ld-api-20120712/
</ins></a></dd><dt><ins class="diff-new">
Latest
published
version:
</ins></dt><dd><a href="http://www.w3.org/TR/json-ld-api/"><ins class="diff-new">
http://www.w3.org/TR/json-ld-api/
</ins></a></dd><dt>
Latest
editor's
draft:
</dt>
<dd>
<del class="diff-old">http://json-ld.org/spec/latest/json-ld-api/
</del>
<a href="http://dvcs.w3.org/hg/json-ld/raw-file/default/spec/latest/json-ld-api/index.html">
<ins class="diff-chg">http://dvcs.w3.org/hg/json-ld/raw-file/default/spec/latest/json-ld-api/index.html
</ins>
</a>
</dd>
<dt>
Editors:
</dt>
<dd rel="bibo:editor" inlist="">
<span typeof="foaf:Person">
<a rel="foaf:homepage" property="foaf:name" content="Manu Sporny" href="http://manu.sporny.org/">
Manu
Sporny
</a>,
<a rel="foaf:workplaceHomepage" href="http://digitalbazaar.com/">
Digital
Bazaar
</a>
</span>
</dd>
<dd rel="bibo:editor" inlist="">
<span typeof="foaf:Person">
<a rel="foaf:homepage" property="foaf:name" content="Gregg Kellogg" href="http://greggkellogg.net/">
Gregg
Kellogg
</a>,
<a rel="foaf:workplaceHomepage" href="http://kellogg-assoc.com/">
Kellogg
Associates
</a>
</span>
</dd>
<dd rel="bibo:editor" inlist="">
<span typeof="foaf:Person">
<a rel="foaf:homepage" property="foaf:name" content="Dave Longley" href="http://digitalbazaar.com/">
Dave
Longley
</a>,
<a rel="foaf:workplaceHomepage" href="http://digitalbazaar.com/">
Digital
Bazaar
</a>
</span>
</dd>
<dd rel="bibo:editor" inlist="">
<span typeof="foaf:Person">
<a rel="foaf:homepage" property="foaf:name" content="Markus Lanthaler" href="http://www.markus-lanthaler.com/">
Markus
Lanthaler
</a>,
<a rel="foaf:workplaceHomepage" href="http://www.tugraz.at/">
Graz
University
of
Technology
</a>
</span>
</dd>
<dt>
Authors:
</dt>
<dd rel="dcterms:contributor">
<span typeof="foaf:Person">
<a rel="foaf:homepage" property="foaf:name" content="Dave Longley" href="http://digitalbazaar.com/">
Dave
Longley
</a>,
<a rel="foaf:workplaceHomepage" href="http://digitalbazaar.com/">
Digital
Bazaar
</a>
</span>
</dd>
<dd rel="dcterms:contributor">
<span typeof="foaf:Person">
<a rel="foaf:homepage" property="foaf:name" content="Manu Sporny" href="http://digitalbazaar.com/">
Manu
Sporny
</a>,
<a rel="foaf:workplaceHomepage" href="http://digitalbazaar.com/">
Digital
Bazaar
</a>
</span>
</dd>
<dd rel="dcterms:contributor">
<span typeof="foaf:Person">
<a rel="foaf:homepage" property="foaf:name" content="Gregg Kellogg" href="http://greggkellogg.net/">
Gregg
Kellogg
</a>,
<a rel="foaf:workplaceHomepage" href="http://kellogg-assoc.com/">
Kellogg
Associates
</a>
</span>
</dd>
<dd rel="dcterms:contributor">
<span typeof="foaf:Person">
<a rel="foaf:homepage" property="foaf:name" content="Markus Lanthaler" href="http://www.markus-lanthaler.com/">
Markus
Lanthaler
</a>,
<a rel="foaf:workplaceHomepage" href="http://www.tugraz.at/">
Graz
University
of
Technology
</a>
</span>
</dd>
</dl>
<p>
This
document
is
also
available
in
this
non-normative
format:
<a href="diff-20120626.html">
diff
to
previous
version
</a>
</p>
<p class="copyright">
<a href="http://www.w3.org/Consortium/Legal/ipr-notice#Copyright">
Copyright
</a>
©
2010-2012
<del class="diff-old">the
Contributors
to
the
JSON-LD
API
1.0
Specification,
published
by
the
JSON
for
Linking
Data
Community
Group
</del>
<a href="http://www.w3.org/">
<acronym title="World Wide Web Consortium">
<ins class="diff-chg">W3C
</ins></acronym>
</a>
<del class="diff-old">under
the
</del>
<sup>
<ins class="diff-chg">®
</ins></sup><ins class="diff-chg">
(
</ins><a href="http://www.csail.mit.edu/"><acronym title="Massachusetts Institute of Technology"><ins class="diff-chg">
MIT
</ins></acronym></a>,<a href="http://www.ercim.eu/"><acronym title="European Research Consortium for Informatics and Mathematics"><ins class="diff-chg">
ERCIM
</ins></acronym></a>,<a href="http://www.keio.ac.jp/"><ins class="diff-chg">
Keio
</ins></a><ins class="diff-chg">
),
All
Rights
Reserved.
</ins><acronym title="World Wide Web Consortium">
W3C
<del class="diff-old">Community
Final
Specification
Agreement
(FSA)
.
A
human-readable
summary
</del>
</acronym>
<a href="http://www.w3.org/Consortium/Legal/ipr-notice#Legal_Disclaimer">
<ins class="diff-chg">liability
</ins></a>,<a href="http://www.w3.org/Consortium/Legal/ipr-notice#W3C_Trademarks"><ins class="diff-chg">
trademark
</ins>
</a>
<del class="diff-old">is
available.
</del>
<ins class="diff-chg">and
</ins><a href="http://www.w3.org/Consortium/Legal/copyright-documents"><ins class="diff-chg">
document
use
</ins></a><ins class="diff-chg">
rules
apply.
</ins>
</p>
<hr />
</div>
<div id="abstract" class="introductory section">
<h2>
Abstract
</h2>
<p>
JSON
[
<cite>
<a class="bibref" rel="biblioentry" href="#bib-RFC4627">
RFC4627
</a>
</cite>
]
has
proven
to
be
a
highly
useful
object
serialization
and
messaging
format.
JSON-LD
[
<cite>
<a class="bibref" rel="biblioentry" href="#bib-JSON-LD">
JSON-LD
</a>
</cite>
]
harmonizes
the
representation
of
Linked
Data
in
JSON
by
outlining
a
common
JSON
representation
format
for
expressing
directed
graphs;
mixing
both
Linked
Data
and
non-Linked
Data
in
a
single
document.
This
document
outlines
an
Application
Programming
Interface
and
a
set
of
algorithms
for
programmatically
transforming
JSON-LD
documents
in
order
to
make
them
easier
to
work
with
in
programming
environments
like
JavaScript,
Python,
and
Ruby.
</p>
</div>
<div id="sotd" class="introductory section">
<h2>
Status
of
This
Document
</h2>
<p>
<em>
This
<del class="diff-old">specification
was
published
by
</del>
<ins class="diff-chg">section
describes
</ins>
the
<del class="diff-old">JSON
for
Linking
Data
Community
Group
.
It
is
not
a
W3C
Standard
nor
is
it
on
</del>
<ins class="diff-chg">status
of
this
document
at
</ins>
the
<ins class="diff-new">time
of
its
publication.
Other
documents
may
supersede
this
document.
A
list
of
current
</ins><acronym title="World Wide Web Consortium">
W3C
<del class="diff-old">Standards
Track.
Please
note
that
under
</del>
</acronym>
<ins class="diff-chg">publications
and
</ins>
the
<ins class="diff-chg">latest
revision
of
this
technical
report
can
be
found
in
the
</ins><a href="http://www.w3.org/TR/"><acronym title="World Wide Web Consortium">
W3C
<del class="diff-old">Community
Final
Specification
Agreement
(FSA)
</del>
</acronym>
<ins class="diff-chg">technical
reports
index
</ins>
</a>
<del class="diff-old">other
conditions
apply.
Learn
more
about
W3C
Community
and
Business
Groups
.
</del>
<ins class="diff-chg">at
http://www.w3.org/TR/.
</ins></em>
</p>
<p>
This
document
has
been
under
development
for
over
18
months
in
the
JSON
for
Linking
Data
Community
Group.
The
document
has
recently
been
<del class="diff-old">approved
for
transfer
into
</del>
<ins class="diff-chg">transferred
to
</ins>
the
RDF
Working
Group
for
<del class="diff-old">review
with
the
intent
to
publish
the
document
</del>
<ins class="diff-chg">review,
improvement,
and
publication
</ins>
along
the
<del class="diff-old">W3C
</del>
Recommendation
track.
<del class="diff-old">This
</del>
<ins class="diff-chg">While
this
is
a
First
Public
Working
Draft
publication,
the
</ins>
specification
has
undergone
significant
development,
review,
and
changes
during
the
course
of
the
last
18
months
and
is
<del class="diff-old">being
published
as
a
Final
Community
Group
Specification
so
that
it
may
gain
wider
review
and
feedback.
</del>
<ins class="diff-chg">more
mature
than
the
First
Public
Working
Draft
status
implies.
</ins>
</p>
<p>
There
are
currently
<a href="http://json-ld.org/#impl">
five
interoperable
implementations
</a>
of
this
specification.
There
is
a
<a href="https://github.com/json-ld/json-ld.org/tree/main/test-suite">
fairly
complete
test
suite
</a>
and
a
<a href="http://json-ld.org/playground/">
live
JSON-LD
editor
</a>
that
is
capable
of
demonstrating
the
features
described
in
this
document.
While
development
on
implementations,
the
test
suite
and
the
live
editor
will
continue,
they
are
believed
to
be
mature
enough
to
be
integrated
into
a
non-production
system
at
this
point
in
time
with
the
expectation
that
they
could
be
used
in
a
production
system
within
the
next
year.
</p>
<div class="issue">
<div class="issue-title">
<span>
Issue
1
</span>
</div>
<p class="">
It
is
important
for
readers
to
understand
that
the
scope
of
this
document
is
currently
under
debate
and
new
features
may
be
added
to
the
specification.
Existing
features
may
be
modified
heavily
or
removed
entirely
from
the
specification
upon
further
review
and
feedback
from
the
broader
community.
This
is
a
work
in
progress
and
publication
as
a
First
Public
Working
Draft
does
not
require
that
all
Working
Group
members
agree
on
the
content
of
the
document.
</p>
</div>
<p>
<ins class="diff-new">This
document
was
published
by
the
</ins><a href="http://www.w3.org/2011/rdf-wg/"><ins class="diff-new">
RDF
Working
Group
</ins></a><ins class="diff-new">
as
a
First
Public
Working
Draft.
This
document
is
intended
to
become
a
</ins><acronym title="World Wide Web Consortium"><ins class="diff-new">
W3C
</ins></acronym><ins class="diff-new">
Recommendation.
If
you
wish
to
make
comments
regarding
this
document,
please
send
them
to
</ins><a href="mailto:public-rdf-comments@w3.org"><ins class="diff-new">
public-rdf-comments@w3.org
</ins></a><ins class="diff-new">
(
</ins><a href="mailto:public-rdf-comments-request@w3.org?subject=subscribe"><ins class="diff-new">
subscribe
</ins></a>,<a href="http://lists.w3.org/Archives/Public/public-rdf-comments/"><ins class="diff-new">
archives
</ins></a><ins class="diff-new">
).
All
feedback
is
welcome.
</ins></p><p><ins class="diff-new">
Publication
as
a
Working
Draft
does
not
imply
endorsement
by
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</ins><acronym title="World Wide Web Consortium"><ins class="diff-new">
W3C
</ins></acronym><ins class="diff-new">
Membership.
This
is
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draft
document
and
may
be
updated,
replaced
or
obsoleted
by
other
documents
at
any
time.
It
is
inappropriate
to
cite
this
document
as
other
than
work
in
progress.
</ins></p><p><ins class="diff-new">
This
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produced
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operating
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</ins><a href="http://www.w3.org/Consortium/Patent-Policy-20040205/"><ins class="diff-new">
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February
2004
</ins><acronym title="World Wide Web Consortium"><ins class="diff-new">
W3C
</ins></acronym><ins class="diff-new">
Patent
Policy
</ins></a>.<acronym title="World Wide Web Consortium"><ins class="diff-new">
W3C
</ins></acronym><ins class="diff-new">
maintains
a
</ins><a href="http://www.w3.org/2004/01/pp-impl/46168/status" rel="disclosure"><ins class="diff-new">
public
list
of
any
patent
disclosures
</ins></a><ins class="diff-new">
made
in
connection
with
the
deliverables
of
the
group;
that
page
also
includes
instructions
for
disclosing
a
patent.
An
individual
who
has
actual
knowledge
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the
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believes
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</ins><a href="http://www.w3.org/Consortium/Patent-Policy-20040205/#def-essential"><ins class="diff-new">
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W3C
</ins></acronym><ins class="diff-new">
Patent
Policy
</ins></a>.</p>
</div>
<div id="toc" class="section">
<h2 class="introductory">
Table
of
Contents
</h2>
<ul class="toc">
<li class="tocline">
<a href="#preface" class="tocxref">
<span class="secno">
1.
</span>
Preface
</a>
<ul class="toc">
<li class="tocline">
<a href="#contributing" class="tocxref">
<span class="secno">
1.1
</span>
Contributing
</a>
</li>
</ul>
</li>
<li class="tocline">
<a href="#introduction" class="tocxref">
<span class="secno">
2.
</span>
Introduction
</a>
<ul class="toc">
<li class="tocline">
<a href="#expansion" class="tocxref">
<span class="secno">
2.1
</span>
Expansion
</a>
</li>
<li class="tocline">
<a href="#compaction" class="tocxref">
<span class="secno">
2.2
</span>
Compaction
</a>
</li>
<li class="tocline">
<a href="#conversion-to-and-from-rdf" class="tocxref">
<span class="secno">
2.3
</span>
Conversion
to
and
from
RDF
</a>
</li>
<li class="tocline">
<a href="#framing-and-normalization" class="tocxref">
<span class="secno">
2.4
</span>
Framing
and
Normalization
</a>
</li>
</ul>
</li>
<li class="tocline">
<a href="#the-application-programming-interface" class="tocxref">
<span class="secno">
3.
</span>
The
Application
Programming
Interface
</a>
<ul class="toc">
<li class="tocline">
<a href="#general-terminology" class="tocxref">
<span class="secno">
3.1
</span>
General
Terminology
</a>
</li>
<li class="tocline">
<a href="#jsonldprocessor" class="tocxref">
<span class="secno">
3.2
</span>
JsonLdProcessor
</a>
<ul class="toc">
<li class="tocline">
<a href="#methods" class="tocxref">
<span class="secno">
3.2.1
</span>
Methods
</a>
</li>
</ul>
</li>
<li class="tocline">
<a href="#callbacks" class="tocxref">
<span class="secno">
3.3
</span>
Callbacks
</a>
<ul class="toc">
<li class="tocline">
<a href="#jsonldcallback" class="tocxref">
<span class="secno">
3.3.1
</span>
JsonLdCallback
</a>
<ul class="toc">
<li class="tocline">
<a href="#methods-1" class="tocxref">
<span class="secno">
3.3.1.1
</span>
Methods
</a>
</li>
</ul>
</li>
<li class="tocline">
<a href="#quadcallback" class="tocxref">
<span class="secno">
3.3.2
</span>
QuadCallback
</a>
<ul class="toc">
<li class="tocline">
<a href="#methods-2" class="tocxref">
<span class="secno">
3.3.2.1
</span>
Methods
</a>
</li>
</ul>
</li>
</ul>
</li>
<li class="tocline">
<a href="#data-structures" class="tocxref">
<span class="secno">
3.4
</span>
Data
Structures
</a>
<ul class="toc">
<li class="tocline">
<a href="#url" class="tocxref">
<span class="secno">
3.4.1
</span>
URL
</a>
</li>
<li class="tocline">
<a href="#jsonldoptions" class="tocxref">
<span class="secno">
3.4.2
</span>
JsonLdOptions
</a>
</li>
<li class="tocline">
<a href="#quad" class="tocxref">
<span class="secno">
3.4.3
</span>
Quad
</a>
<ul class="toc">
<li class="tocline">
<a href="#attributes" class="tocxref">
<span class="secno">
3.4.3.1
</span>
Attributes
</a>
</li>
</ul>
</li>
<li class="tocline">
<a href="#node" class="tocxref">
<span class="secno">
3.4.4
</span>
Node
</a>
</li>
<li class="tocline">
<a href="#iri" class="tocxref">
<span class="secno">
3.4.5
</span>
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
<ul class="toc">
<li class="tocline">
<a href="#attributes-1" class="tocxref">
<span class="secno">
3.4.5.1
</span>
Attributes
</a>
</li>
</ul>
</li>
<li class="tocline">
<a href="#blank-node" class="tocxref">
<span class="secno">
3.4.6
</span>
<span title="blank_node">
Blank
Node
</span>
</a>
<ul class="toc">
<li class="tocline">
<a href="#attributes-2" class="tocxref">
<span class="secno">
3.4.6.1
</span>
Attributes
</a>
</li>
</ul>
</li>
<li class="tocline">
<a href="#literal" class="tocxref">
<span class="secno">
3.4.7
</span>
Literal
</a>
<ul class="toc">
<li class="tocline">
<a href="#attributes-3" class="tocxref">
<span class="secno">
3.4.7.1
</span>
Attributes
</a>
</li>
</ul>
</li>
</ul>
</li>
</ul>
</li>
<li class="tocline">
<a href="#algorithms" class="tocxref">
<span class="secno">
4.
</span>
Algorithms
</a>
<ul class="toc">
<li class="tocline">
<a href="#algorithm-terms" class="tocxref">
<span class="secno">
4.1
</span>
Algorithm
Terms
</a>
</li>
<li class="tocline">
<a href="#context-processing" class="tocxref">
<span class="secno">
4.2
</span>
Context
Processing
</a>
</li>
<li class="tocline">
<a href="#iri-expansion" class="tocxref">
<span class="secno">
4.3
</span>
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
Expansion
</a>
</li>
<li class="tocline">
<a href="#iri-compaction" class="tocxref">
<span class="secno">
4.4
</span>
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
Compaction
</a>
<ul class="toc">
<li class="tocline">
<a href="#iri-compaction-algorithm" class="tocxref">
<span class="secno">
4.4.1
</span>
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
Compaction
Algorithm
</a>
</li>
<li class="tocline">
<a href="#term-rank-algorithm" class="tocxref">
<span class="secno">
4.4.2
</span>
Term
Rank
Algorithm
</a>
</li>
</ul>
</li>
<li class="tocline">
<a href="#value-expansion" class="tocxref">
<span class="secno">
4.5
</span>
Value
Expansion
</a>
</li>
<li class="tocline">
<a href="#value-compaction" class="tocxref">
<span class="secno">
4.6
</span>
Value
Compaction
</a>
</li>
<li class="tocline">
<a href="#expansion-1" class="tocxref">
<span class="secno">
4.7
</span>
Expansion
</a>
<ul class="toc">
<li class="tocline">
<a href="#expansion-algorithm" class="tocxref">
<span class="secno">
4.7.1
</span>
Expansion
Algorithm
</a>
</li>
</ul>
</li>
<li class="tocline">
<a href="#compaction-1" class="tocxref">
<span class="secno">
4.8
</span>
Compaction
</a>
<ul class="toc">
<li class="tocline">
<a href="#compaction-algorithm" class="tocxref">
<span class="secno">
4.8.1
</span>
Compaction
Algorithm
</a>
</li>
</ul>
</li>
<li class="tocline">
<a href="#rdf-conversion" class="tocxref">
<span class="secno">
4.9
</span>
RDF
Conversion
</a>
<ul class="toc">
<li class="tocline">
<a href="#overview" class="tocxref">
<span class="secno">
4.9.1
</span>
Overview
</a>
</li>
<li class="tocline">
<a href="#parsing-examples" class="tocxref">
<span class="secno">
4.9.2
</span>
Parsing
Examples
</a>
</li>
<li class="tocline">
<a href="#convert-to-rdf-algorithm" class="tocxref">
<span class="secno">
4.9.3
</span>
Convert
to
RDF
Algorithm
</a>
</li>
<li class="tocline">
<a href="#list-conversion" class="tocxref">
<span class="secno">
4.9.4
</span>
List
Conversion
</a>
</li>
<li class="tocline">
<a href="#convert-from-rdf-algorithm" class="tocxref">
<span class="secno">
4.9.5
</span>
Convert
from
RDF
Algorithm
</a>
</li>
</ul>
</li>
</ul>
</li>
<li class="tocline">
<a href="#data-round-tripping" class="tocxref">
<span class="secno">
5.
</span>
Data
Round
Tripping
</a>
</li>
<li class="tocline">
<a href="#appendix-a" class="tocxref">
<span class="secno">
A.
</span>
Initial
Context
</a>
</li>
<li class="tocline">
<a href="#acknowledgements" class="tocxref">
<span class="secno">
B.
</span>
Acknowledgements
</a>
</li>
<li class="tocline">
<a href="#references" class="tocxref">
<span class="secno">
C.
</span>
References
</a>
<ul class="toc">
<li class="tocline">
<a href="#normative-references" class="tocxref">
<span class="secno">
C.1
</span>
Normative
references
</a>
</li>
<li class="tocline">
<a href="#informative-references" class="tocxref">
<span class="secno">
C.2
</span>
Informative
references
</a>
</li>
</ul>
</li>
</ul>
</div>
<div id="preface" class="section">
<h2>
<span class="secno">
1.
</span>
Preface
</h2>
<p>
This
document
is
a
detailed
specification
for
an
Application
Programming
Interface
for
the
JSON-LD
Syntax.
The
document
is
primarily
intended
for
the
following
audiences:
</p>
<ul>
<li>
Web
authors
and
developers
that
want
a
very
detailed
view
of
how
a
JSON-LD
processor
and
the
API
operates.
</li>
<li>
Software
developers
that
want
to
implement
processors
and
APIs
for
JSON-LD.
</li>
</ul>
<p>
To
understand
the
basics
in
this
specification
you
must
first
be
familiar
with
JSON,
which
is
detailed
in
[
<cite>
<a class="bibref" rel="biblioentry" href="#bib-RFC4627">
RFC4627
</a>
</cite>
].
You
must
also
understand
the
JSON-LD
Syntax
[
<cite>
<a class="bibref" rel="biblioentry" href="#bib-JSON-LD">
JSON-LD
</a>
</cite>
],
which
is
the
base
syntax
used
by
all
of
the
algorithms
in
this
document.
To
understand
the
API
and
how
it
is
intended
to
operate
in
a
programming
environment,
it
is
useful
to
have
working
knowledge
of
the
JavaScript
programming
language
[
<cite>
<a class="bibref" rel="biblioentry" href="#bib-ECMA-262">
ECMA-262
</a>
</cite>
]
and
WebIDL
[
<cite>
<a class="bibref" rel="biblioentry" href="#bib-WEBIDL">
WEBIDL
</a>
</cite>
].
To
understand
how
JSON-LD
maps
to
RDF,
it
is
helpful
to
be
familiar
with
the
basic
RDF
concepts
[
<cite>
<a class="bibref" rel="biblioentry" href="#bib-RDF-CONCEPTS">
RDF-CONCEPTS
</a>
</cite>
].
</p>
<div id="contributing" class="section">
<h3>
<span class="secno">
1.1
</span>
Contributing
</h3>
<p>
There
are
a
number
of
ways
that
one
may
participate
in
the
development
of
this
specification:
</p>
<ul>
<li>
If
you
want
to
make
sure
that
your
feedback
is
formally
addressed
by
the
RDF
Working
Group,
you
should
send
it
to
public-rdf-comments:
<a href="http://lists.w3.org/Archives/Public/public-rdf-comments/">
public-rdf-comments@w3.org
</a>
</li>
<li>
Ad-hoc
technical
discussion
primarily
occurs
on
the
public
community
mailing
list:
<a href="http://lists.w3.org/Archives/Public/public-linked-json/">
public-linked-json@w3.org
</a>
</li>
<li>
<a href="http://json-ld.org/minutes/">
Public
JSON-LD
Community
Group
teleconferences
</a>
are
held
on
Tuesdays
at
1500UTC
every
week.
</li>
<li>
RDF
Working
Group
teleconferences
are
held
on
Wednesdays
at
1500UTC
every
week.
Participation
is
limited
to
RDF
Working
Group
members.
</li>
<li>
Specification
bugs
and
issues
should
be
reported
in
the
<a href="https://github.com/json-ld/json-ld.org/issues">
issue
tracker
</a>
if
you
do
not
want
to
send
an
e-mail
to
the
public-rdf-comments
mailing
list.
</li>
<li>
<a href="https://github.com/json-ld/json-ld.org/tree/main/spec">
Source
code
</a>
for
the
specification
can
be
found
on
Github.
</li>
<li>
The
<a href="http://webchat.freenode.net/?channels=json-ld">
#json-ld
</a>
IRC
channel
is
available
for
real-time
discussion
on
irc.freenode.net.
</li>
</ul>
</div>
</div>
<div id="introduction" class="section">
<h2>
<span class="secno">
2.
</span>
Introduction
</h2>
<p>
The
JSON-LD
Syntax
specification
[
<cite>
<a class="bibref" rel="biblioentry" href="#bib-JSON-LD">
JSON-LD
</a>
</cite>
]
outlines
a
language
that
may
be
used
to
express
Linked
Data
in
JSON.
Often,
it
is
useful
to
be
able
to
transform
JSON-LD
documents
so
that
they
may
be
easily
processed
in
a
programming
environment
like
JavaScript,
Python
or
Ruby.
</p>
<p>
There
are
three
major
types
of
transformation
that
are
discussed
in
this
document;
compaction,
expansion,
and
RDF
conversion.
</p>
<div id="expansion" class="section">
<h3>
<span class="secno">
2.1
</span>
Expansion
</h3>
<p>
Software
algorithms
are
easiest
to
write
when
the
data
that
they
are
processing
have
a
regular
form.
Since
information
can
be
represented
by
JSON-LD
in
a
variety
of
different
ways,
transforming
all
of
these
methods
into
a
uniform
structure
allows
the
developer
to
simplify
their
processing
code.
For
example,
note
that
the
following
input
uses
only
<a class="tref internalDFN" title="term" href="#dfn-term">
term
</a>
s
and
is
fairly
compact:
</p>
  <div class="example"><div class="example-title"><span>Example 1</span></div><pre class="example">var input1 = {
  &quot;@context&quot;: &quot;http://json-ld.org/contexts/person.jsonld&quot;
  &quot;name&quot;: &quot;Manu Sporny&quot;,
  &quot;homepage&quot;: &quot;http://manu.sporny.org/&quot;
}
</pre>
</div>
<p>
The
next
input
example
uses
one
<a class="tref internalDFN" title="iri" href="#dfn-iri">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
to
express
a
property,
but
leaves
the
rest
of
the
information
untouched.
</p>
  <div class="example"><div class="example-title"><span>Example 2</span></div><pre class="example">var input2 = {
  &quot;@context&quot;: &quot;http://json-ld.org/contexts/person.jsonld&quot;
  &quot;<span class="diff">http://xmlns.com/foaf/0.1/name</span>&quot;: &quot;Manu Sporny&quot;,
  &quot;homepage&quot;: &quot;http://manu.sporny.org/&quot;
}
</pre>
</div>
<p>
While
both
inputs
are
valid
JSON-LD,
writing
a
program
to
handle
every
permutation
of
possible
inputs
can
be
difficult,
especially
when
the
incoming
context
could
change
as
well.
To
ensure
that
the
data
can
be
given
a
more
uniform
structure,
JSON-LD
introduces
the
notion
of
expansion.
<dfn title="expansion" id="dfn-expansion">
Expansion
</dfn>
performs
two
important
operations.
The
first
is
to
expand
all
values
that
are
<a class="tref internalDFN" title="iri" href="#dfn-iri">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
s
to
their
fully
expanded
form.
The
second
is
to
express
all
values
in
<dfn title="expanded_form" id="dfn-expanded_form">
expanded
form
</dfn>.
To
transform
both
inputs
above
to
the
same
representation,
the
developer
could
do
the
following:
</p>
  <div class="example"><div class="example-title"><span>Example 3</span></div><pre class="example">function expansionCallback(output) {
   console.log(output);
}
// the second parameter is 'null' because the developer does not wish to
// inject another context value
jsonld.expand(input1, null, expansionCallback);
jsonld.expand(input2,
null,
expansionCallback);
</pre>
</div>
<p>
The
output
for
both
calls
above
will
be:
</p>
  <div class="example"><div class="example-title"><span>Example 4</span></div><pre class="example">[{
  &quot;http://xmlns.com/foaf/0.1/name&quot;: [{
    &quot;@value&quot;: &quot;Manu Sporny&quot;
  }],
  &quot;http://xmlns.com/foaf/0.1/homepage&quot;: [{
    &quot;@id&quot;: &quot;http://manu.sporny.org/&quot;
  }]
}]
</pre>
</div>
<p>
Note
that
in
the
example
above;
all
<a class="tref internalDFN" title="context" href="#dfn-context">
context
</a>
definitions
have
been
removed,
all
<a class="tref internalDFN" title="term" href="#dfn-term">
term
</a>
and
prefixes
have
been
expanded
to
full
IRIs,
and
all
<a class="tref internalDFN" title="literal" href="#dfn-literal">
literal
</a>
s
are
expressed
in
<a class="tref internalDFN" title="expanded_form" href="#dfn-expanded_form">
expanded
form
</a>.
While
the
output
is
more
difficult
for
a
human
to
read,
it
is
easier
for
a
software
program
to
process
because
of
its
very
regular
structure.
</p>
</div>
<div id="compaction" class="section">
<h3>
<span class="secno">
2.2
</span>
Compaction
</h3>
<p>
While
expansion
expands
a
given
input
as
much
as
possible,
compaction
performs
the
opposite
operation
-
expressing
a
given
input
as
succinctly
as
possible.
While
expansion
is
meant
to
produce
something
that
is
easy
to
process
by
software
programs,
compaction
is
meant
to
produce
something
that
is
easy
to
ready
by
software
developers.
Compaction
uses
a
developer-supplied
<a class="tref internalDFN" title="context" href="#dfn-context">
context
</a>
to
compresses
all
<a class="tref internalDFN" title="iri" href="#dfn-iri">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
s
to
<a class="tref internalDFN" title="term" href="#dfn-term">
term
</a>
s
or
<a class="tref internalDFN" title="prefix" href="#dfn-prefix">
prefix
</a>
es,
and
compacts
all
<a class="tref internalDFN" title="literal" href="#dfn-literal">
literal
</a>
s
expressed
in
<a class="tref internalDFN" title="expanded_form" href="#dfn-expanded_form">
expanded
form
</a>
as
much
as
possible.
</p>
<p>
The
following
example
expresses
input
that
has
already
been
fully
expanded:
</p>
  <div class="example"><div class="example-title"><span>Example 5</span></div><pre class="example">var expandedInput = [{
  &quot;http://xmlns.com/foaf/0.1/name&quot;: [{
    &quot;@value&quot;: &quot;Manu Sporny&quot;
  }],
  &quot;http://xmlns.com/foaf/0.1/homepage&quot;: [{
    &quot;@id&quot;: &quot;http://manu.sporny.org/&quot;
  }]
}]
</pre>
</div>
<p>
A
developer
that
wants
to
transform
the
data
above
into
a
more
human-readable
form,
could
do
the
following
using
the
JSON-LD
API:
</p>
  <div class="example"><div class="example-title"><span>Example 6</span></div><pre class="example">function compactionCallback(output) {
   console.log(output);
}
jsonld.compact(expandedInput,
&quot;http://json-ld.org/contexts/person.jsonld&quot;,
compactionCallback);
</pre>
</div>
<p>
The
following
would
be
the
result
of
the
call
above:
</p>
  <div class="example"><div class="example-title"><span>Example 7</span></div><pre class="example">{
  &quot;@context&quot;: &quot;http://json-ld.org/contexts/person.jsonld&quot;
  &quot;name&quot;: &quot;Manu Sporny&quot;,
  &quot;homepage&quot;: &quot;http://manu.sporny.org/&quot;
}
</pre>
</div>
<p>
Note
that
all
of
the
<a class="tref internalDFN" title="term" href="#dfn-term">
term
</a>
s
have
been
compressed
and
the
<a class="tref internalDFN" title="context" href="#dfn-context">
context
</a>
has
been
injected
into
the
output.
While
compacted
output
is
most
useful
to
humans,
it
can
also
be
carefully
used
to
generate
structures
that
are
easy
to
use
for
developers
to
program
against
as
well.
</p>
</div>
<div id="conversion-to-and-from-rdf" class="section">
<h3>
<span class="secno">
2.3
</span>
Conversion
to
and
from
RDF
</h3>
<p>
JSON-LD
can
be
used
to
losslessly
express
the
RDF
data
model
as
described
in
the
RDF
Concepts
document
[
<cite>
<a class="bibref" rel="biblioentry" href="#bib-RDF-CONCEPTS">
RDF-CONCEPTS
</a>
</cite>
].
This
ensures
that
data
can
be
round-tripped
from
any
RDF
syntax,
like
N-Triples
or
TURTLE,
without
any
loss
in
the
fidelity
of
the
data.
Assume
the
following
RDF
input
in
N-Triples
format:
</p>
  <div class="example"><div class="example-title"><span>Example 8</span></div><pre class="example">var data = &quot;
&lt;http://manu.sporny.org/about/#manu&gt; &lt;http://xmlns.com/foaf/0.1/name&gt; \&quot;Manu Sporny\&quot; .\n
&lt;http://manu.sporny.org/about/#manu&gt;
&lt;http://xmlns.com/foaf/0.1/homepage&gt;
&lt;http://manu.sporny.org/&gt;
.&quot;;
</pre>
</div>
<p>
A
developer
can
use
the
JSON-LD
API
to
transform
the
markup
above
into
a
JSON-LD
document:
</p>
  <div class="example"><div class="example-title"><span>Example 9</span></div><pre class="example">function conversionCallback(result)
{
  console.log(&quot;JSON-LD Document: &quot;, result);
};
jsonld.fromRDF(data,
conversionCallback,
{&quot;format&quot;:
&quot;ntriples&quot;});
</pre>
</div>
<p>
The
following
expanded
output
would
be
the
result
of
the
call
above:
</p>
  <div class="example"><div class="example-title"><span>Example 10</span></div><pre class="example">[{
  &quot;@id&quot;: &quot;http://manu.sporny.org/about/#manu&quot;,
  &quot;http://xmlns.com/foaf/0.1/name&quot;: [{
    &quot;@value&quot;: &quot;Manu Sporny&quot;
  }],
  &quot;http://xmlns.com/foaf/0.1/homepage&quot;: [{
    &quot;@id&quot;: &quot;http://manu.sporny.org/&quot;
  }]
}]
</pre>
</div>
<p>
Note
that
the
output
above,
could
easily
be
compacted
to
produce
the
following
using
the
technique
outlined
in
the
previous
section:
</p>
  <div class="example"><div class="example-title"><span>Example 11</span></div><pre class="example">{
  &quot;@context&quot;: &quot;http://json-ld.org/contexts/person.jsonld&quot;,
  &quot;@id&quot;: &quot;http://manu.sporny.org/about/#manu&quot;,
  &quot;name&quot;: &quot;Manu Sporny&quot;,
  &quot;homepage&quot;: &quot;http://manu.sporny.org/&quot;
}
</pre>
</div>
<p>
Transforming
the
object
above
back
to
RDF
is
as
simple
as
calling
the
<code>
toRDF()
</code>
method:
</p>
  <div class="example"><div class="example-title"><span>Example 12</span></div><pre class="example">var jsonldDocument = ...; // assign the JSON-LD document here
function rdfCallback(quads)
{
  console.log(&quot;RDF Data: &quot;, quads);
};
jsonld.toRDF(jsonldDocument,
rdfCallback);
</pre>
</div>
</div>
<div id="framing-and-normalization" class="section">
<h3>
<span class="secno">
2.4
</span>
Framing
and
Normalization
</h3>
<div class="issue">
<div class="issue-title">
<span>
Issue
2
</span>
</div>
<p class="">
There
are
currently
two
other
API
methods
that
are
in
active
development
and
were
not
ready
for
publication
at
the
time
this
document
was
published.
Framing
allows
a
developer
to
force
a
different
layout
for
the
data
and
effectively
perform
query-by-example
on
JSON-LD
documents
-
this
is
most
useful
when
a
JSON-LD-based
REST
API
does
not
know
the
exact
form
of
the
data
it
is
getting
in,
but
still
wants
to
operate
upon
it
if
some
bare
essentials
are
found
in
the
data.
JSON-LD
normalization
allows
JSON-LD
documents
to
be
deterministically
serialized
such
that
they
can
be
digitally
signed
or
be
used
to
find
the
differences
between
two
<a class="tref internalDFN" title="linked_data_graph" href="#dfn-linked_data_graph">
linked
data
graph
</a>
s.
It
is
expected
that
framing
will
be
a
part
of
the
final
API.
It
is
expected
that
normalization
will
be
an
optional
feature
that
JSON-LD
processors
may
implement.
</p>
</div>
</div>
</div>
<div id="the-application-programming-interface" class="section">
<h2>
<span class="secno">
3.
</span>
The
Application
Programming
Interface
</h2>
<p>
This
API
provides
a
clean
mechanism
that
enables
developers
to
convert
JSON-LD
data
into
a
a
variety
of
output
formats
that
are
easier
to
work
with
in
various
programming
languages.
If
a
JSON-LD
API
is
provided
in
a
programming
environment,
the
entirety
of
the
following
API
<em class="rfc2119" title="must">
must
</em>
be
implemented.
</p>
<div id="general-terminology" class="section">
<h3>
<span class="secno">
3.1
</span>
General
Terminology
</h3>
<div class="issue">
<div class="issue-title">
<span>
Issue
3
</span>
</div>
<p class="">
The
intent
of
the
Working
Group
and
the
Editors
of
this
specification
is
to
eventually
align
terminology
used
in
this
document
with
the
terminology
used
in
the
RDF
Concepts
document
to
the
extent
to
which
it
makes
sense
to
do
so.
In
general,
if
there
is
an
analogue
to
terminology
used
in
this
document
in
the
RDF
Concepts
document,
the
preference
is
to
use
the
terminology
in
the
RDF
Concepts
document.
</p>
</div>
<p>
The
following
is
an
explanation
of
the
general
terminology
used
in
this
document:
</p>
<dl>
<dt>
<dfn title="json_object" id="dfn-json_object">
JSON
object
</dfn>
</dt>
<dd>
An
object
structure
is
represented
as
a
pair
of
curly
brackets
surrounding
zero
or
more
name-value
pairs.
A
name
is
a
<a class="tref internalDFN" title="string" href="#dfn-string">
string
</a>.
A
single
colon
comes
after
each
name,
separating
the
name
from
the
value.
A
single
comma
separates
a
value
from
a
following
name.
The
names
within
an
object
<em class="rfc2119" title="should">
should
</em>
be
unique.
</dd>
<dt>
<dfn title="array" id="dfn-array">
array
</dfn>
</dt>
<dd>
An
array
is
represented
as
square
brackets
surrounding
zero
or
more
values
that
are
separated
by
commas.
</dd>
<dt>
<dfn title="string" id="dfn-string">
string
</dfn>
</dt>
<dd>
A
string
is
a
sequence
of
zero
or
more
Unicode
(UTF-8)
characters,
wrapped
in
double
quotes,
using
backslash
escapes
(if
necessary).
A
character
is
represented
as
a
single
character
string.
</dd>
<dt>
<dfn title="number" id="dfn-number">
number
</dfn>
</dt>
<dd>
A
number
is
similar
to
that
used
in
most
programming
languages,
except
that
the
octal
and
hexadecimal
formats
are
not
used
and
that
leading
zeros
are
not
allowed.
</dd>
<dt>
<dfn title="true" id="dfn-true">
true
</dfn>
and
<dfn title="false" id="dfn-false">
false
</dfn>
</dt>
<dd>
Values
that
are
used
to
express
one
of
two
possible
boolean
states.
</dd>
<dt>
<dfn title="null" id="dfn-null">
null
</dfn>
</dt>
<dd>
Unless
otherwise
specified,
a
JSON-LD
processor
<em class="rfc2119" title="must">
must
</em>
act
as
if
a
key-value
pair
in
the
body
of
a
JSON-LD
document
was
never
declared
when
the
value
equals
<em>
null
</em>.
If
<code>
@value
</code>,
<code>
@list
</code>,
or
<code>
@set
</code>
is
set
to
<em>
null
</em>
in
expanded
form,
then
the
entire
JSON
object
is
ignored.
If
<code>
@context
</code>
is
set
to
<em>
null
</em>,
the
<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
active
context
</a>
is
reset
and
when
used
within
a
<a class="tref internalDFN" title="context" href="#dfn-context">
context
</a>,
it
removes
any
definition
associated
with
the
key,
unless
otherwise
specified.
</dd>
<dt>
<dfn title="subject_definition" id="dfn-subject_definition">
subject
definition
</dfn>
</dt>
<dd>
A
<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
JSON
object
</a>
used
to
represent
a
<a class="tref internalDFN" title="subject" href="#dfn-subject">
subject
</a>
and
one
or
more
properties
of
that
subject.
A
<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
JSON
object
</a>
is
a
subject
definition
if
it
does
not
contain
they
keys
<code>
@value
</code>,
<code>
@list
</code>
or
<code>
@set
</code>
and
it
has
one
or
more
keys
other
than
<code>
@id
</code>.
</dd>
<dt>
<dfn title="subject_reference" id="dfn-subject_reference">
subject
reference
</dfn>
</dt>
<dd>
A
<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
JSON
object
</a>
used
to
reference
a
subject
having
only
the
<code>
@id
</code>
key.
</dd>
<dt>
<dfn title="linked_data" id="dfn-linked_data">
Linked
Data
</dfn>
</dt>
<dd>
A
set
of
documents,
each
containing
a
representation
of
a
<a class="tref internalDFN" title="linked_data_graph" href="#dfn-linked_data_graph">
linked
data
graph
</a>.
</dd>
<dt>
<dfn title="linked_data_graph" id="dfn-linked_data_graph">
linked
data
graph
</dfn>
or
<dfn title="dataset" id="dfn-dataset">
dataset
</dfn>
</dt>
<dd>
An
unordered
labeled
directed
graph,
where
<a class="tref internalDFN" title="node" href="#dfn-node">
node
</a>
s
are
<a class="tref internalDFN" title="subject" href="#dfn-subject">
subject
</a>
s
or
<a class="tref internalDFN" title="object" href="#dfn-object">
object
</a>
s,
and
edges
are
properties.
</dd>
<dt>
<dfn title="node" id="dfn-node">
node
</dfn>
</dt>
<dd>
A
piece
of
information
that
is
represented
in
a
<a class="tref internalDFN" title="linked_data_graph" href="#dfn-linked_data_graph">
linked
data
graph
</a>.
</dd>
<dt>
<dfn title="named_graph" id="dfn-named_graph">
named
graph
</dfn>
</dt>
<dd>
A
<a class="tref internalDFN" title="linked_data_graph" href="#dfn-linked_data_graph">
linked
data
graph
</a>
that
has
one
or
more
<a class="tref internalDFN" title="iri" href="#dfn-iri">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
that
are
used
to
refer
to
it.
</dd>
<dt>
<dfn title="graph_name" id="dfn-graph_name">
graph
name
</dfn>
</dt>
<dd>
An
<a class="tref internalDFN" title="iri" href="#dfn-iri">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
that
is
a
reference
to
a
<a class="tref internalDFN" title="named_graph" href="#dfn-named_graph">
named
graph
</a>.
</dd>
<dt>
<dfn title="default_graph" id="dfn-default_graph">
default
graph
</dfn>
</dt>
<dd>
When
executing
an
algorithm,
the
graph
where
data
should
be
placed
if
a
<a class="tref internalDFN" title="named_graph" href="#dfn-named_graph">
named
graph
</a>
is
not
specified.
</dd>
<dt>
<dfn title="subject" id="dfn-subject">
subject
</dfn>
</dt>
<dd>
Any
node
in
a
<a class="tref internalDFN" title="linked_data_graph" href="#dfn-linked_data_graph">
linked
data
graph
</a>
with
at
least
one
outgoing
edge.
</dd>
<dt>
<dfn title="iri" id="dfn-iri">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</dfn>
</dt>
<dd>
An
Internationalized
Resource
Identifier
as
described
in
[
<cite>
<a class="bibref" rel="biblioentry" href="#bib-RFC3987">
RFC3987
</a>
</cite>
]).
</dd>
<dt>
<dfn title="object" id="dfn-object">
object
</dfn>
</dt>
<dd>
A
node
in
a
<a class="tref internalDFN" title="linked_data_graph" href="#dfn-linked_data_graph">
linked
data
graph
</a>
with
at
least
one
incoming
edge.
</dd>
<dt>
<dfn title="property" id="dfn-property">
property
</dfn>
</dt>
<dd>
An
edge
of
the
<a class="tref internalDFN" title="linked_data_graph" href="#dfn-linked_data_graph">
linked
data
graph
</a>.
</dd>
<dt>
<dfn title="literal" id="dfn-literal">
literal
</dfn>
</dt>
<dd>
An
<a class="tref internalDFN" title="object" href="#dfn-object">
object
</a>
with
a
label
that
is
not
an
<a class="tref internalDFN" title="iri" href="#dfn-iri">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>.
</dd>
<dt>
<dfn title="quad" id="dfn-quad">
quad
</dfn>
</dt>
<dd>
A
piece
of
information
that
contains
four
items;
a
<a class="tref internalDFN" title="subject" href="#dfn-subject">
subject
</a>,
a
<a class="tref internalDFN" title="property" href="#dfn-property">
property
</a>,
a
<a class="tref internalDFN" title="object" href="#dfn-object">
object
</a>,
and
a
<a class="tref internalDFN" title="graph_name" href="#dfn-graph_name">
graph
name
</a>.
</dd>
<dt>
<dfn title="context" id="dfn-context">
context
</dfn>
</dt>
<dd>
A
<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
JSON
object
</a>
that
contains
rules
for
interpreting
a
JSON-LD
document.
</dd>
<dt>
<dfn title="keyword" id="dfn-keyword">
keyword
</dfn>
</dt>
<dd>
A
JSON
key
that
is
specific
to
JSON-LD,
specified
in
the
JSON-LD
Syntax
specification
[
<cite>
<a class="bibref" rel="biblioentry" href="#bib-JSON-LD">
JSON-LD
</a>
</cite>
]
in
the
section
titled
<a href="http://sites.local/json-ld.org/spec/latest/json-ld-syntax/#syntax-tokens-and-keywords">
Syntax
Tokens
and
Keywords
</a>.
</dd>
</dl>
</div>
<div id="jsonldprocessor" class="section">
<h3>
<span class="secno">
3.2
</span>
JsonLdProcessor
</h3>
<p>
The
JSON-LD
Processor
interface
is
the
high-level
programming
structure
that
developers
use
to
access
the
JSON-LD
transformation
methods.
</p>
    <pre class="idl"><span class="idlInterface" id="idl-def-JsonLdProcessor">[<span class="extAttr">NoInterfaceObject</span>]
interface <span class="idlInterfaceID">JsonLdProcessor</span> {
<span class="idlMethod">    <span class="idlMethType"><a>void</a></span> <span class="idlMethName"><a href="#widl-JsonLdProcessor-expand-void-object-or-object---or-URL-input-object-or-URL-context-JsonLdCallback-callback-JsonLdOptions-options">expand</a></span> (<span class="idlParam"><span class="idlParamType"><a>object or object[] or URL</a></span> <span class="idlParamName">input</span></span>, <span class="idlParam"><span class="idlParamType"><a>object or URL</a>?</span> <span class="idlParamName">context</span></span>, <span class="idlParam"><span class="idlParamType"><a href="#idl-def-JsonLdCallback" class="idlType"><code>JsonLdCallback</code></a></span> <span class="idlParamName">callback</span></span>, <span class="idlParam">optional <span class="idlParamType"><a href="#idl-def-JsonLdOptions" class="idlType"><code>JsonLdOptions</code></a></span> <span class="idlParamName">options</span></span>);</span>
<span class="idlMethod">    <span class="idlMethType"><a>void</a></span> <span class="idlMethName"><a href="#widl-JsonLdProcessor-compact-void-object-or-object---or-URL-input-object-or-URL-context-JsonLdCallback-callback-JsonLdOptions-options">compact</a></span> (<span class="idlParam"><span class="idlParamType"><a>object or object[] or URL</a></span> <span class="idlParamName">input</span></span>, <span class="idlParam"><span class="idlParamType"><a>object or URL</a></span> <span class="idlParamName">context</span></span>, <span class="idlParam"><span class="idlParamType"><a href="#idl-def-JsonLdCallback" class="idlType"><code>JsonLdCallback</code></a></span> <span class="idlParamName">callback</span></span>, <span class="idlParam">optional <span class="idlParamType"><a href="#idl-def-JsonLdOptions" class="idlType"><code>JsonLdOptions</code></a></span> <span class="idlParamName">options</span></span>);</span>
<span class="idlMethod">    <span class="idlMethType"><a>void</a></span> <span class="idlMethName"><a href="#widl-JsonLdProcessor-fromRDF-void-QuadArray-input-JsonLdCallback-callback-JsonLdOptions-options">fromRDF</a></span> (<span class="idlParam"><span class="idlParamType"><a href="#idl-def-Quad" class="idlType"><code>Quad</code></a>[]</span> <span class="idlParamName">input</span></span>, <span class="idlParam"><span class="idlParamType"><a href="#idl-def-JsonLdCallback" class="idlType"><code>JsonLdCallback</code></a></span> <span class="idlParamName">callback</span></span>, <span class="idlParam">optional <span class="idlParamType"><a href="#idl-def-JsonLdOptions" class="idlType"><code>JsonLdOptions</code></a></span> <span class="idlParamName">options</span></span>);</span>
<span class="idlMethod">    <span class="idlMethType"><a>void</a></span> <span class="idlMethName"><a href="#widl-JsonLdProcessor-toRDF-void-object-or-object---or-URL-input-QuadCallback-callback-JsonLdOptions-options">toRDF</a></span> (<span class="idlParam"><span class="idlParamType"><a>object or object[] or URL</a></span> <span class="idlParamName">input</span></span>, <span class="idlParam"><span class="idlParamType"><a href="#idl-def-QuadCallback" class="idlType"><code>QuadCallback</code></a></span> <span class="idlParamName">callback</span></span>, <span class="idlParam">optional <span class="idlParamType"><a href="#idl-def-JsonLdOptions" class="idlType"><code>JsonLdOptions</code></a></span> <span class="idlParamName">options</span></span>);</span>
};</span>
</pre>
<div id="methods" class="section">
<h2>
<span class="secno">
3.2.1
</span>
Methods
</h2>
<dl class="methods">
<dt id="widl-JsonLdProcessor-compact-void-object-or-object---or-URL-input-object-or-URL-context-JsonLdCallback-callback-JsonLdOptions-options">
<code>
compact
</code>
</dt>
<dd>
<a href="#compaction">
Compacts
</a>
the
given
<code>
input
</code>
using
the
<code>
context
</code>
according
to
the
steps
in
the
<a href="#compaction-algorithm">
Compaction
Algorithm
</a>.
The
<code>
input
</code>
<em class="rfc2119" title="must">
must
</em>
be
copied,
compacted
and
returned
if
there
are
no
errors.
If
the
compaction
fails,
an
appropriate
exception
<em class="rfc2119" title="must">
must
</em>
be
thrown.
<table class="parameters">
<tr>
<th>
Parameter
</th>
<th>
Type
</th>
<th>
Nullable
</th>
<th>
Optional
</th>
<th>
Description
</th>
</tr>
<tr>
<td class="prmName">
input
</td>
<td class="prmType">
<code>
<a>
object
or
object[]
or
URL
</a>
</code>
</td>
<td class="prmNullFalse">
✘
</td>
<td class="prmOptFalse">
✘
</td>
<td class="prmDesc">
The
JSON-LD
object
or
array
of
JSON-LD
objects
to
perform
the
compaction
upon
or
an
<a class="tref internalDFN" title="iri" href="#dfn-iri">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
referencing
the
JSON-LD
document
to
compact.
</td>
</tr>
<tr>
<td class="prmName">
context
</td>
<td class="prmType">
<code>
<a>
object
or
URL
</a>
</code>
</td>
<td class="prmNullFalse">
✘
</td>
<td class="prmOptFalse">
✘
</td>
<td class="prmDesc">
The
context
to
use
when
compacting
the
<code>
input
</code>
;
either
in
the
form
of
an
<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
JSON
object
</a>
or
as
<a class="tref internalDFN" title="iri" href="#dfn-iri">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>.
</td>
</tr>
<tr>
<td class="prmName">
callback
</td>
<td class="prmType">
<code>
<a href="#idl-def-JsonLdCallback" class="idlType">
<code>
JsonLdCallback
</code>
</a>
</code>
</td>
<td class="prmNullFalse">
✘
</td>
<td class="prmOptFalse">
✘
</td>
<td class="prmDesc">
A
callback
that
is
called
when
processing
is
complete
on
the
given
<code>
input
</code>.
</td>
</tr>
<tr>
<td class="prmName">
options
</td>
<td class="prmType">
<code>
<a href="#idl-def-JsonLdOptions" class="idlType">
<code>
JsonLdOptions
</code>
</a>
</code>
</td>
<td class="prmNullFalse">
✘
</td>
<td class="prmOptTrue">
✔
</td>
<td class="prmDesc">
A
set
of
options
that
<em class="rfc2119" title="may">
may
</em>
affect
the
expansion
algorithm
such
as,
e.g.,
the
input
document's
base
<a class="tref internalDFN" title="iri" href="#dfn-iri">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>.
This
also
includes
<code>
optimize
</code>,
which
if
set
will
cause
processor-specific
optimization.
</td>
</tr>
</table>
<div>
<em>
Return
type:
</em>
<code>
<a>
void
</a>
</code>
</div>
</dd>
<dt id="widl-JsonLdProcessor-expand-void-object-or-object---or-URL-input-object-or-URL-context-JsonLdCallback-callback-JsonLdOptions-options">
<code>
expand
</code>
</dt>
<dd>
<a href="#expansion">
Expands
</a>
the
given
<code>
input
</code>
according
to
the
steps
in
the
<a href="#expansion-algorithm">
Expansion
Algorithm
</a>.
The
<code>
input
</code>
<em class="rfc2119" title="must">
must
</em>
be
copied,
expanded
and
returned
if
there
are
no
errors.
If
the
expansion
fails,
an
appropriate
exception
<em class="rfc2119" title="must">
must
</em>
be
thrown.
<table class="parameters">
<tr>
<th>
Parameter
</th>
<th>
Type
</th>
<th>
Nullable
</th>
<th>
Optional
</th>
<th>
Description
</th>
</tr>
<tr>
<td class="prmName">
input
</td>
<td class="prmType">
<code>
<a>
object
or
object[]
or
URL
</a>
</code>
</td>
<td class="prmNullFalse">
✘
</td>
<td class="prmOptFalse">
✘
</td>
<td class="prmDesc">
The
JSON-LD
object
or
array
of
JSON-LD
objects
to
perform
the
expansion
upon
or
an
<a class="tref internalDFN" title="iri" href="#dfn-iri">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
referencing
the
JSON-LD
document
to
expand.
</td>
</tr>
<tr>
<td class="prmName">
context
</td>
<td class="prmType">
<code>
<a>
object
or
URL
</a>
</code>
</td>
<td class="prmNullTrue">
✔
</td>
<td class="prmOptFalse">
✘
</td>
<td class="prmDesc">
An
optional
external
context
to
use
additionally
to
the
context
embedded
in
<code>
input
</code>
when
expanding
the
<code>
input
</code>.
</td>
</tr>
<tr>
<td class="prmName">
callback
</td>
<td class="prmType">
<code>
<a href="#idl-def-JsonLdCallback" class="idlType">
<code>
JsonLdCallback
</code>
</a>
</code>
</td>
<td class="prmNullFalse">
✘
</td>
<td class="prmOptFalse">
✘
</td>
<td class="prmDesc">
A
callback
that
is
called
when
processing
is
complete
on
the
given
<code>
input
</code>.
</td>
</tr>
<tr>
<td class="prmName">
options
</td>
<td class="prmType">
<code>
<a href="#idl-def-JsonLdOptions" class="idlType">
<code>
JsonLdOptions
</code>
</a>
</code>
</td>
<td class="prmNullFalse">
✘
</td>
<td class="prmOptTrue">
✔
</td>
<td class="prmDesc">
A
set
of
options
that
<em class="rfc2119" title="may">
may
</em>
affect
the
expansion
algorithm
such
as,
e.g.,
the
input
document's
base
<a class="tref internalDFN" title="iri" href="#dfn-iri">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>.
</td>
</tr>
</table>
<div>
<em>
Return
type:
</em>
<code>
<a>
void
</a>
</code>
</div>
</dd>
<dt id="widl-JsonLdProcessor-fromRDF-void-QuadArray-input-JsonLdCallback-callback-JsonLdOptions-options">
<code>
fromRDF
</code>
</dt>
<dd>
Creates
a
JSON-LD
document
given
an
set
of
<a class="datatype idlType" title="quad" href="#idl-def-quad">
<code>
Quads
</code>
</a>.
<table class="parameters">
<tr>
<th>
Parameter
</th>
<th>
Type
</th>
<th>
Nullable
</th>
<th>
Optional
</th>
<th>
Description
</th>
</tr>
<tr>
<td class="prmName">
input
</td>
<td class="prmType">
<code>
<a href="#idl-def-Quad" class="idlType">
<code>
Quad
</code>
</a>
[]
</code>
</td>
<td class="prmNullFalse">
✘
</td>
<td class="prmOptFalse">
✘
</td>
<td class="prmDesc">
A
<a class="tref internalDFN" title="dataset" href="#dfn-dataset">
dataset
</a>
represented
as
an
array
of
<a class="datatype idlType" title="quad" href="#idl-def-quad">
<code>
Quads
</code>
</a>.
</td>
</tr>
<tr>
<td class="prmName">
callback
</td>
<td class="prmType">
<code>
<a href="#idl-def-JsonLdCallback" class="idlType">
<code>
JsonLdCallback
</code>
</a>
</code>
</td>
<td class="prmNullFalse">
✘
</td>
<td class="prmOptFalse">
✘
</td>
<td class="prmDesc">
A
callback
that
is
called
when
processing
is
complete
on
the
given
<code>
input
</code>.
</td>
</tr>
<tr>
<td class="prmName">
options
</td>
<td class="prmType">
<code>
<a href="#idl-def-JsonLdOptions" class="idlType">
<code>
JsonLdOptions
</code>
</a>
</code>
</td>
<td class="prmNullFalse">
✘
</td>
<td class="prmOptTrue">
✔
</td>
<td class="prmDesc">
A
set
of
options
that
will
affect
the
algorithm.
This
includes
<code>
notType
</code>,
which
if
set
to
<a class="tref internalDFN" title="true" href="#dfn-true">
true
</a>
causes
the
resulting
document
to
use
<code>
rdf:type
</code>
as
a
property,
instead
of
<code>
@type
</code>.
</td>
</tr>
</table>
<div>
<em>
Return
type:
</em>
<code>
<a>
void
</a>
</code>
</div>
</dd>
<dt id="widl-JsonLdProcessor-toRDF-void-object-or-object---or-URL-input-QuadCallback-callback-JsonLdOptions-options">
<code>
toRDF
</code>
</dt>
<dd>
Processes
the
<code>
input
</code>
according
to
the
<a href="#convert-to-rdf-algorithm">
Convert
to
RDF
Algorithm
</a>,
calling
the
provided
<code>
callback
</code>
for
each
<a class="datatype idlType" title="Quad" href="#idl-def-Quad">
<code>
Quad
</code>
</a>
generated.
<table class="parameters">
<tr>
<th>
Parameter
</th>
<th>
Type
</th>
<th>
Nullable
</th>
<th>
Optional
</th>
<th>
Description
</th>
</tr>
<tr>
<td class="prmName">
input
</td>
<td class="prmType">
<code>
<a>
object
or
object[]
or
URL
</a>
</code>
</td>
<td class="prmNullFalse">
✘
</td>
<td class="prmOptFalse">
✘
</td>
<td class="prmDesc">
The
JSON-LD
object
or
array
of
JSON-LD
objects
to
convert
to
RDF
or
a
<a href="#idl-def-URL" class="idlType">
<code>
URL
</code>
</a>
referencing
the
JSON-LD
document
to
convert
to
RDF.
</td>
</tr>
<tr>
<td class="prmName">
callback
</td>
<td class="prmType">
<code>
<a href="#idl-def-QuadCallback" class="idlType">
<code>
QuadCallback
</code>
</a>
</code>
</td>
<td class="prmNullFalse">
✘
</td>
<td class="prmOptFalse">
✘
</td>
<td class="prmDesc">
A
callback
that
is
called
when
a
<a class="datatype idlType" title="Quad" href="#idl-def-Quad">
<code>
Quad
</code>
</a>
is
created
from
processing
the
given
<code>
input
</code>.
</td>
</tr>
<tr>
<td class="prmName">
options
</td>
<td class="prmType">
<code>
<a href="#idl-def-JsonLdOptions" class="idlType">
<code>
JsonLdOptions
</code>
</a>
</code>
</td>
<td class="prmNullFalse">
✘
</td>
<td class="prmOptTrue">
✔
</td>
<td class="prmDesc">
A
set
of
options
that
<em class="rfc2119" title="may">
may
</em>
affect
the
conversion
to
RDF
such
as,
e.g.,
the
input
document's
base
<a class="tref internalDFN" title="iri" href="#dfn-iri">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>.
</td>
</tr>
</table>
<div>
<em>
Return
type:
</em>
<code>
<a>
void
</a>
</code>
</div>
</dd>
</dl>
</div>
</div>
<div id="callbacks" class="section">
<h3>
<span class="secno">
3.3
</span>
Callbacks
</h3>
<div id="jsonldcallback" class="section">
<h4>
<span class="secno">
3.3.1
</span>
JsonLdCallback
</h4>
<p>
The
<a href="#idl-def-JsonLdCallback" class="idlType">
<code>
JsonLdCallback
</code>
</a>
is
used
to
return
a
processed
JSON-LD
representation
as
the
result
of
processing
an
API
method.
</p>
    <pre class="idl"><span class="idlInterface" id="idl-def-JsonLdCallback">[<span class="extAttr">NoInterfaceObject Callback</span>]
interface <span class="idlInterfaceID">JsonLdCallback</span> {
<span class="idlMethod">    <span class="idlMethType"><a>void</a></span> <span class="idlMethName"><a href="#widl-JsonLdCallback-jsonLd-void-object-or-objectArray-jsonld">jsonLd</a></span> (<span class="idlParam"><span class="idlParamType"><a>object or object</a>[]</span> <span class="idlParamName">jsonld</span></span>);</span>
};</span>
</pre>
<div id="methods-1" class="section">
<h2>
<span class="secno">
3.3.1.1
</span>
Methods
</h2>
<dl class="methods">
<dt id="widl-JsonLdCallback-jsonLd-void-object-or-objectArray-jsonld">
<code>
jsonLd
</code>
</dt>
<dd>
This
callback
is
invoked
when
processing
is
complete.
<table class="parameters">
<tr>
<th>
Parameter
</th>
<th>
Type
</th>
<th>
Nullable
</th>
<th>
Optional
</th>
<th>
Description
</th>
</tr>
<tr>
<td class="prmName">
jsonld
</td>
<td class="prmType">
<code>
<a>
object
or
object
</a>
[]
</code>
</td>
<td class="prmNullFalse">
✘
</td>
<td class="prmOptFalse">
✘
</td>
<td class="prmDesc">
The
processed
JSON-LD
document.
</td>
</tr>
</table>
<div>
<em>
Return
type:
</em>
<code>
<a>
void
</a>
</code>
</div>
</dd>
</dl>
</div>
</div>
<div id="quadcallback" class="section">
<h4>
<span class="secno">
3.3.2
</span>
QuadCallback
</h4>
<p>
The
<a href="#idl-def-QuadCallback" class="idlType">
<code>
QuadCallback
</code>
</a>
is
called
whenever
the
processor
generates
a
quad
during
the
<code>
quad()
</code>
call.
</p>
    <pre class="idl"><span class="idlInterface" id="idl-def-QuadCallback">[<span class="extAttr">NoInterfaceObject Callback</span>]
interface <span class="idlInterfaceID">QuadCallback</span> {
<span class="idlMethod">    <span class="idlMethType"><a>void</a></span> <span class="idlMethName"><a href="#widl-QuadCallback-quad-void-Quad-quad">quad</a></span> (<span class="idlParam"><span class="idlParamType"><a href="#idl-def-Quad" class="idlType"><code>Quad</code></a></span> <span class="idlParamName">quad</span></span>);</span>
};</span>
</pre>
<div id="methods-2" class="section">
<h2>
<span class="secno">
3.3.2.1
</span>
Methods
</h2>
<dl class="methods">
<dt id="widl-QuadCallback-quad-void-Quad-quad">
<code>
quad
</code>
</dt>
<dd>
This
callback
is
invoked
whenever
a
quad
is
generated
by
the
processor.
<table class="parameters">
<tr>
<th>
Parameter
</th>
<th>
Type
</th>
<th>
Nullable
</th>
<th>
Optional
</th>
<th>
Description
</th>
</tr>
<tr>
<td class="prmName">
quad
</td>
<td class="prmType">
<code>
<a href="#idl-def-Quad" class="idlType">
<code>
Quad
</code>
</a>
</code>
</td>
<td class="prmNullFalse">
✘
</td>
<td class="prmOptFalse">
✘
</td>
<td class="prmDesc">
The
quad.
</td>
</tr>
</table>
<div>
<em>
Return
type:
</em>
<code>
<a>
void
</a>
</code>
</div>
</dd>
</dl>
</div>
</div>
</div>
<div id="data-structures" class="section">
<h3>
<span class="secno">
3.4
</span>
Data
Structures
</h3>
<p>
This
section
describes
datatype
definitions
used
within
the
JSON-LD
API.
</p>
<div id="url" class="section">
<h4>
<span class="secno">
3.4.1
</span>
URL
</h4>
<p>
The
<a href="#idl-def-URL" class="idlType">
<code>
URL
</code>
</a>
datatype
is
a
string
representation
of
an
<a class="tref internalDFN" title="iri" href="#dfn-iri">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>.
</p>
<pre class="idl">
<span class="idlTypedef" id="idl-def-URL">
typedef
<span class="idlTypedefType">
<a>
DOMString
</a>
</span>
<span class="idlTypedefID">
URL
</span>
;
</span>
</pre>
<div class="idlTypedefDesc">
This
datatype
indicates
that
the
<a class="tref internalDFN" title="iri" href="#dfn-iri">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
is
interpreted
as
a
Universal
Resource
Locator
identifying
a
document,
which
when
parsed
as
JSON
yields
either
a
<code>
JSON
object
</code>
or
<code>
array
</code>.
</div>
</div>
<div id="jsonldoptions" class="section">
<h4>
<span class="secno">
3.4.2
</span>
JsonLdOptions
</h4>
<p>
The
<a href="#idl-def-JsonLdOptions" class="idlType">
<code>
JsonLdOptions
</code>
</a>
type
is
used
to
convert
a
set
of
options
to
an
interface
method.
</p>
<pre class="idl">
<span class="idlTypedef" id="idl-def-JsonLdOptions">
typedef
<span class="idlTypedefType">
<a>
object
</a>
</span>
<span class="idlTypedefID">
JsonLdOptions
</span>
;
</span>
</pre>
<div class="idlTypedefDesc">
<dt>
<a href="#idl-def-URL" class="idlType">
<code>
URL
</code>
</a>
base
</dt>
<dd>
The
Base
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
to
use
when
expanding
the
document.
This
overrides
the
value
of
<em>
input
</em>
if
it
is
a
<a href="#idl-def-URL" class="idlType">
<code>
URL
</code>
</a>
or
if
it
is
a
<code>
object
</code>
or
<code>
object[]
</code>.
</dd>
<dt>
boolean
optimize
</dt>
<dd>
If
set
to
<code>
true
</code>,
the
JSON-LD
processor
is
allowed
to
optimize
the
output
of
the
<a href="#compaction-algorithm">
Compaction
Algorithm
</a>
to
produce
even
compacter
representations.
The
algorithm
for
compaction
optimization
is
beyond
the
scope
of
this
specification
and
thus
not
defined.
Consequently,
different
implementations
<em class="rfc2119" title="may">
may
</em>
implement
different
optimization
algorithms.
</dd>
<dt>
boolean
noType
</dt>
<dd>
If
set
to
<code>
true
</code>,
the
JSON-LD
processor
will
not
use
the
<code>
@type
</code>
property
when
generating
the
output,
and
will
use
the
expanded
<code>
rdf:type
</code>
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
as
the
property
instead
of
<code>
@type
</code>.
</dd>
</div>
</div>
<p>
The
following
data
structures
are
used
for
representing
data
about
RDF
quads.
They
are
used
for
normalization,
<a>
fromRDF
</a>,
and
from
<a>
toRDF
</a>
interfaces.
</p>
<div id="quad" class="section">
<h4>
<span class="secno">
3.4.3
</span>
Quad
</h4>
<p>
The
<a href="#idl-def-Quad" class="idlType">
<code>
Quad
</code>
</a>
interface
represents
an
RDF
Quad.
See
[
<cite>
<a class="bibref" rel="biblioentry" href="#bib-RDF-CONCEPTS">
RDF-CONCEPTS
</a>
</cite>
]
definition
for
<cite>
<a href="http://www.w3.org/TR/rdf11-concepts/#dfn-rdf-triple">
RDF
triple
</a>
</cite>,
which
most
closely
aligns
to
<a href="#idl-def-Quad" class="idlType">
<code>
Quad
</code>
</a>.
</p>
    <pre class="idl"><span class="idlInterface" id="idl-def-Quad">[<span class="extAttr">NoInterfaceObject</span>]
interface <span class="idlInterfaceID">Quad</span> {
<span class="idlAttribute">    readonly attribute <span class="idlAttrType"><a href="#idl-def-Node" class="idlType"><code>Node</code></a></span>  <span class="idlAttrName"><a href="#widl-Quad-subject">subject</a></span>;</span>
<span class="idlAttribute">    readonly attribute <span class="idlAttrType"><a href="#idl-def-Node" class="idlType"><code>Node</code></a></span>  <span class="idlAttrName"><a href="#widl-Quad-predicate">predicate</a></span>;</span>
<span class="idlAttribute">    readonly attribute <span class="idlAttrType"><a href="#idl-def-Node" class="idlType"><code>Node</code></a></span>  <span class="idlAttrName"><a href="#widl-Quad-object">object</a></span>;</span>
<span class="idlAttribute">    readonly attribute <span class="idlAttrType"><a href="#idl-def-Node" class="idlType"><code>Node</code></a>?</span> <span class="idlAttrName"><a href="#widl-Quad-graphName">graphName</a></span>;</span>
};</span>
</pre>
<div id="attributes" class="section">
<h2>
<span class="secno">
3.4.3.1
</span>
Attributes
</h2>
<dl class="attributes">
<dt id="widl-Quad-graphName">
<code>
graphName
</code>
of
type
<span class="idlAttrType">
<a href="#idl-def-Node" class="idlType">
<code>
Node
</code>
</a>
</span>,
readonly,
nullable
</dt>
<dd>
If
present,
the
name
associated
with
the
<a href="#idl-def-Quad" class="idlType">
<code>
Quad
</code>
</a>
identifying
it
as
a
member
of
a
<a class="tref internalDFN" title="named_graph" href="#dfn-named_graph">
named
graph
</a>.
If
it
is
missing,
the
quad
is
a
member
of
the
<a class="tref internalDFN" title="default_graph" href="#dfn-default_graph">
default
graph
</a>.
<div class="issue">
<div class="issue-title">
<span>
Issue
4
</span>
</div>
<div class="">
This
element
is
at
risk,
and
may
be
removed.
</div>
</div>
</dd>
<dt id="widl-Quad-object">
<code>
object
</code>
of
type
<span class="idlAttrType">
<a href="#idl-def-Node" class="idlType">
<code>
Node
</code>
</a>
</span>,
readonly
</dt>
<dd>
The
<a class="tref internalDFN" title="object" href="#dfn-object">
object
</a>
associated
with
the
<a href="#idl-def-Quad" class="idlType">
<code>
Quad
</code>
</a>.
</dd>
<dt id="widl-Quad-predicate">
<code>
predicate
</code>
of
type
<span class="idlAttrType">
<a href="#idl-def-Node" class="idlType">
<code>
Node
</code>
</a>
</span>,
readonly
</dt>
<dd>
The
predicate
associated
with
the
<a href="#idl-def-Quad" class="idlType">
<code>
Quad
</code>
</a>.
Within
JSON-LD,
an
<dfn title="rdf_predicate" id="dfn-rdf_predicate">
RDF
predicate
</dfn>
is
refered
to
as
a
<a class="tref internalDFN" title="property" href="#dfn-property">
property
</a>
</dd>
<dt id="widl-Quad-subject">
<code>
subject
</code>
of
type
<span class="idlAttrType">
<a href="#idl-def-Node" class="idlType">
<code>
Node
</code>
</a>
</span>,
readonly
</dt>
<dd>
The
<a class="tref internalDFN" title="subject" href="#dfn-subject">
subject
</a>
associated
with
the
<a href="#idl-def-Quad" class="idlType">
<code>
Quad
</code>
</a>.
</dd>
</dl>
</div>
</div>
<div id="node" class="section">
<h4>
<span class="secno">
3.4.4
</span>
Node
</h4>
<p>
<a class="datatype idlType" title="Node" href="#idl-def-Node">
<code>
Node
</code>
</a>
is
the
base
class
of
<a class="datatype idlType" title="IRI" href="#idl-def-IRI">
<code>
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</code>
</a>,
<a class="datatype idlType" title="BlankNode" href="#idl-def-BlankNode">
<code>
BlankNode
</code>
</a>,
and
<a class="datatype idlType" title="Literal" href="#idl-def-Literal">
<code>
Literal
</code>
</a>.
It
is
the
IDL
representation
of
a
<a class="tref internalDFN" title="linked_data_graph" href="#dfn-linked_data_graph">
linked
data
graph
</a>
<a class="tref internalDFN" title="node" href="#dfn-node">
node
</a>.
</p>
    <pre class="idl"><span class="idlInterface" id="idl-def-Node">[<span class="extAttr">NoInterfaceObject</span>]
interface <span class="idlInterfaceID">Node</span> {
};</span>
</pre>
</div>
<div id="iri" class="section">
<h4>
<span class="secno">
3.4.5
</span>
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</h4>
<p>
A
<a class="tref internalDFN" title="node" href="#dfn-node">
node
</a>
that
is
an
<a class="tref internalDFN" title="iri" href="#dfn-iri">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>.
</p>
    <pre class="idl"><span class="idlInterface" id="idl-def-IRI">[<span class="extAttr">NoInterfaceObject</span>]
interface <span class="idlInterfaceID">IRI</span> : <span class="idlSuperclass"><a href="#idl-def-Node" class="idlType"><code>Node</code></a></span> {
<span class="idlAttribute">    readonly attribute <span class="idlAttrType"><a>DOMString</a></span> <span class="idlAttrName"><a href="#widl-IRI-value">value</a></span>;</span>
};</span>
</pre>
<div id="attributes-1" class="section">
<h2>
<span class="secno">
3.4.5.1
</span>
Attributes
</h2>
<dl class="attributes">
<dt id="widl-IRI-value">
<code>
value
</code>
of
type
<span class="idlAttrType">
<a>
DOMString
</a>
</span>,
readonly
</dt>
<dd>
The
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
identifier
of
the
<a class="tref internalDFN" title="node" href="#dfn-node">
node
</a>
as
a
[
<cite>
<a class="bibref" rel="biblioentry" href="#bib-UNICODE">
UNICODE
</a>
</cite>
]
string.
</dd>
</dl>
</div>
</div>
<div id="blank-node" class="section">
<h4>
<span class="secno">
3.4.6
</span>
<dfn title="blank_node" id="dfn-blank_node">
Blank
Node
</dfn>
</h4>
<p>
A
<a class="tref internalDFN" title="node" href="#dfn-node">
node
</a>
in
the
<a class="tref internalDFN" title="linked_data_graph" href="#dfn-linked_data_graph">
linked
data
graph
</a>
that
does
not
contain
a
de-reference-able
identifier
because
it
is
either
ephemeral
in
nature
or
does
not
contain
information
that
needs
to
be
linked
to
from
outside
of
the
<a class="tref internalDFN" title="linked_data_graph" href="#dfn-linked_data_graph">
linked
data
graph
</a>.
A
blank
node
is
assigned
an
identifier
starting
with
the
prefix
<code>
_:
</code>
and
an
implementation
dependent,
auto-generated
suffix
that
is
unique
to
all
information
associated
with
the
particular
blank
node.
</p>
    <pre class="idl"><span class="idlInterface" id="idl-def-BlankNode">[<span class="extAttr">NoInterfaceObject</span>]
interface <span class="idlInterfaceID">BlankNode</span> : <span class="idlSuperclass"><a href="#idl-def-Node" class="idlType"><code>Node</code></a></span> {
<span class="idlAttribute">    readonly attribute <span class="idlAttrType"><a>DOMString</a></span> <span class="idlAttrName"><a href="#widl-BlankNode-identifier">identifier</a></span>;</span>
};</span>
</pre>
<div id="attributes-2" class="section">
<h2>
<span class="secno">
3.4.6.1
</span>
Attributes
</h2>
<dl class="attributes">
<dt id="widl-BlankNode-identifier">
<code>
identifier
</code>
of
type
<span class="idlAttrType">
<a>
DOMString
</a>
</span>,
readonly
</dt>
<dd>
The
temporary
identifier
of
the
<a class="tref internalDFN" title="blank_node" href="#dfn-blank_node">
blank
node
</a>.
The
<code>
identifier
</code>
<em class="rfc2119" title="must not">
must
not
</em>
be
relied
upon
in
any
way
between
two
separate
processing
runs
of
the
same
document
or
with
a
different
document.
</dd>
</dl>
</div>
<div class="note">
<div class="note-title">
<span>
Note
</span>
</div>
<p class="">
Developers
and
authors
must
not
assume
that
the
value
of
a
<a class="tref internalDFN" title="blank_node" href="#dfn-blank_node">
blank
node
</a>
will
remain
the
same
between
two
processing
runs.
<a href="#idl-def-BlankNode" class="idlType">
<code>
BlankNode
</code>
</a>
values
are
only
valid
for
the
most
recent
processing
run
on
the
document.
<a href="#idl-def-BlankNode" class="idlType">
<code>
BlankNode
</code>
</a>
values
will
often
be
generated
differently
by
different
processors.
</p>
</div>
<div class="note">
<div class="note-title">
<span>
Note
</span>
</div>
<p class="">
Implementers
<em class="rfc2119" title="must">
must
</em>
ensure
that
<a href="#idl-def-BlankNode" class="idlType">
<code>
BlankNode
</code>
</a>
values
are
unique
within
the
current
environment,
two
<a class="datatype idlType" title="blanknode" href="#idl-def-blanknode">
<code>
BlankNodes
</code>
</a>
are
considered
equal
if,
and
only
if,
their
values
are
strictly
equal.
</p>
</div>
</div>
<div id="literal" class="section">
<h4>
<span class="secno">
3.4.7
</span>
Literal
</h4>
<p>
Literals
represent
values
such
as
numbers,
dates
and
strings
in
RDF
data.
A
<a class="datatype idlType" title="Literal" href="#idl-def-Literal">
<code>
Literal
</code>
</a>
is
comprised
of
three
attributes:
</p>
<ul>
<li>
a
lexical
form
of
the
<code>
value
</code>
</li>
<li>
an
optional
<code>
language
</code>
tag
</li>
<li>
a
<code>
datatype
</code>
specified
by
an
<a class="datatype idlType" title="IRI" href="#idl-def-IRI">
<code>
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</code>
</a>
</li>
</ul>
<p>
Literals
representing
plain
text
in
a
natural
language
may
have
a
<code>
language
</code>
tag
specified
by
a
string
token,
as
specified
in
[
<cite>
<a class="bibref" rel="biblioentry" href="#bib-BCP47">
BCP47
</a>
</cite>
],
normalized
to
lowercase
(e.g.,
<code>
'en'
</code>,
<code>
'fr'
</code>,
<code>
'en-gb'
</code>
).
They
also
have
a
datatype
attribute
such
as
<code>
xsd:string
</code>.
If
unspecified,
the
<code>
datatype
</code>
defaults
to
<code>
xsd:string
</code>.
</p>
<p>
Literals
representing
values
with
a
specific
datatype,
such
as
the
integer
72,
may
have
a
<code>
datatype
</code>
attribute
specified
in
the
form
of
a
<a href="#idl-def-IRI" class="idlType">
<code>
IRI
</code>
</a>
(e.g.,
<code>
xsd:integer
</code>
).
</p>
<p>
See[
<cite>
<a class="bibref" rel="biblioentry" href="#bib-RDF-CONCEPTS">
RDF-CONCEPTS
</a>
</cite>
]
definition
for
<cite>
<a href="http://www.w3.org/TR/rdf11-concepts/#dfn-literal">
literal
</a>
</cite>.
</p>
      <pre class="idl"><span class="idlInterface" id="idl-def-Literal">[<span class="extAttr">NoInterfaceObject</span>]
interface <span class="idlInterfaceID">Literal</span> : <span class="idlSuperclass"><a href="#idl-def-Node" class="idlType"><code>Node</code></a></span> {
<span class="idlAttribute">    readonly attribute <span class="idlAttrType"><a>DOMString</a></span>  <span class="idlAttrName"><a href="#widl-Literal-value">value</a></span>;</span>
<span class="idlAttribute">    readonly attribute <span class="idlAttrType"><a>DOMString</a>?</span> <span class="idlAttrName"><a href="#widl-Literal-language">language</a></span>;</span>
<span class="idlAttribute">    readonly attribute <span class="idlAttrType"><a href="#idl-def-IRI" class="idlType"><code>IRI</code></a>?</span>       <span class="idlAttrName"><a href="#widl-Literal-datatype">datatype</a></span>;</span>
};</span>
</pre>
<div id="attributes-3" class="section">
<h2>
<span class="secno">
3.4.7.1
</span>
Attributes
</h2>
<dl class="attributes">
<dt id="widl-Literal-datatype">
<code>
datatype
</code>
of
type
<span class="idlAttrType">
<a href="#idl-def-IRI" class="idlType">
<code>
IRI
</code>
</a>
</span>,
readonly,
nullable
</dt>
<dd>
An
optional
datatype
identified
by
a
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>.
</dd>
<dt id="widl-Literal-language">
<code>
language
</code>
of
type
<span class="idlAttrType">
<a>
DOMString
</a>
</span>,
readonly,
nullable
</dt>
<dd>
An
optional
language
tag
as
defined
in
[
<cite>
<a class="bibref" rel="biblioentry" href="#bib-BCP47">
BCP47
</a>
</cite>
],
normalized
to
lowercase.
</dd>
<dt id="widl-Literal-value">
<code>
value
</code>
of
type
<span class="idlAttrType">
<a>
DOMString
</a>
</span>,
readonly
</dt>
<dd>
The
lexical
form
of
the
Literal's
value.
</dd>
</dl>
</div>
</div>
</div>
</div>
<div id="algorithms" class="section">
<h2>
<span class="secno">
4.
</span>
Algorithms
</h2>
<p>
All
algorithms
described
in
this
section
are
intended
to
operate
on
language-native
data
structures.
That
is,
the
serialization
to
a
text-based
JSON
document
isn't
required
as
input
or
output
to
any
of
these
algorithms
and
language-native
data
structures
<em class="rfc2119" title="must">
must
</em>
be
used
where
applicable.
</p>
<div id="algorithm-terms" class="section">
<h3>
<span class="secno">
4.1
</span>
Algorithm
Terms
</h3>
<dl>
<dt>
<dfn title="initial_context" id="dfn-initial_context">
initial
context
</dfn>
</dt>
<dd>
a
context
that
is
specified
to
the
algorithm
before
processing
begins.
The
contents
of
the
initial
context
is
defined
in
<a href="#appendix-a">
Appendix
A
</a>.
</dd>
<dt>
<dfn title="active_subject" id="dfn-active_subject">
active
subject
</dfn>
</dt>
<dd>
the
currently
active
subject
that
the
processor
should
use
when
processing.
</dd>
<dt>
<dfn title="active_property" id="dfn-active_property">
active
property
</dfn>
</dt>
<dd>
the
currently
active
property
that
the
processor
should
use
when
processing.
The
active
property
is
represented
in
the
original
lexical
form,
which
is
used
for
finding
coercion
mappings
in
the
<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
active
context
</a>.
</dd>
<dt>
<dfn title="active_object" id="dfn-active_object">
active
object
</dfn>
</dt>
<dd>
the
currently
active
object
that
the
processor
should
use
when
processing.
</dd>
<dt>
<dfn title="active_context" id="dfn-active_context">
active
context
</dfn>
</dt>
<dd>
a
context
that
is
used
to
resolve
<a class="tref internalDFN" title="term" href="#dfn-term">
term
</a>
s
while
the
processing
algorithm
is
running.
The
<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
active
context
</a>
is
the
context
contained
within
the
<a class="tref internalDFN" title="processor_state" href="#dfn-processor_state">
processor
state
</a>.
</dd>
<dt>
<dfn title="compact_iri" id="dfn-compact_iri">
compact
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</dfn>
</dt>
<dd>
a
compact
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
is
has
the
form
of
<a class="tref internalDFN" title="prefix" href="#dfn-prefix">
prefix
</a>
and
<em>
suffix
</em>
and
is
used
as
a
way
of
expressing
an
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
without
needing
to
define
separate
<a class="tref internalDFN" title="term" href="#dfn-term">
term
</a>
definitions
for
each
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
contained
within
a
common
vocabulary
identified
by
<a class="tref internalDFN" title="prefix" href="#dfn-prefix">
prefix
</a>.
</dd>
<dt>
<dfn title="local_context" id="dfn-local_context">
local
context
</dfn>
</dt>
<dd>
a
context
that
is
specified
within
a
<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
JSON
object
</a>,
specified
via
the
<code>
@context
</code>
<a class="tref internalDFN" title="keyword" href="#dfn-keyword">
keyword
</a>.
</dd>
<dt>
<dfn title="processor_state" id="dfn-processor_state">
processor
state
</dfn>
</dt>
<dd>
the
<a class="tref internalDFN" title="processor_state" href="#dfn-processor_state">
processor
state
</a>,
which
includes
the
<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
active
context
</a>,
<a class="tref internalDFN" title="active_subject" href="#dfn-active_subject">
active
subject
</a>,
and
<a class="tref internalDFN" title="active_property" href="#dfn-active_property">
active
property
</a>.
The
<a class="tref internalDFN" title="processor_state" href="#dfn-processor_state">
processor
state
</a>
is
managed
as
a
stack
with
elements
from
the
previous
<a class="tref internalDFN" title="processor_state" href="#dfn-processor_state">
processor
state
</a>
copied
into
a
new
<a class="tref internalDFN" title="processor_state" href="#dfn-processor_state">
processor
state
</a>
when
entering
a
new
<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
JSON
object
</a>.
</dd>
<dt>
<dfn title="json-ld_input" id="dfn-json-ld_input">
JSON-LD
input
</dfn>
</dt>
<dd>
The
JSON-LD
data
structure
that
is
provided
as
input
to
the
algorithm.
</dd>
<dt>
<dfn title="json-ld_output" id="dfn-json-ld_output">
JSON-LD
output
</dfn>
</dt>
<dd>
The
JSON-LD
data
structure
that
is
produced
as
output
by
the
algorithm.
</dd>
<dt>
<dfn title="term" id="dfn-term">
term
</dfn>
</dt>
<dd>
A
<a class="tref internalDFN" title="term" href="#dfn-term">
term
</a>
is
a
short
word
defined
in
a
context
that
<em class="rfc2119" title="may">
may
</em>
be
expanded
to
an
<a class="tref internalDFN" title="iri" href="#dfn-iri">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
</dd>
<dt>
<dfn title="prefix" id="dfn-prefix">
prefix
</dfn>
</dt>
<dd>
A
<a class="tref internalDFN" title="prefix" href="#dfn-prefix">
prefix
</a>
is
a
<a class="tref internalDFN" title="term" href="#dfn-term">
term
</a>
that
expands
to
a
vocabulary
base
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>.
It
is
typically
used
along
with
a
<em>
suffix
</em>
to
form
a
<a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">
compact
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
to
create
an
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
within
a
vocabulary.
</dd>
<dt>
<dfn title="language-tagged_literal" id="dfn-language-tagged_literal">
language-tagged
literal
</dfn>
</dt>
<dd>
A
<a class="tref internalDFN" title="language-tagged_literal" href="#dfn-language-tagged_literal">
language-tagged
literal
</a>
is
a
<a class="tref internalDFN" title="literal" href="#dfn-literal">
literal
</a>
without
a
datatype,
including
a
language.
See
<cite>
<a href="http://www.w3.org/TR/rdf11-concepts/#dfn-language-tagged-literal">
languaged-tagged
literal
</a>
</cite>
in
[
<cite>
<a class="bibref" rel="biblioentry" href="#bib-RDF-CONCEPTS">
RDF-CONCEPTS
</a>
</cite>
].
</dd>
<dt>
<dfn title="typed_literal" id="dfn-typed_literal">
typed
literal
</dfn>
</dt>
<dd>
A
<a class="tref internalDFN" title="typed_literal" href="#dfn-typed_literal">
typed
literal
</a>
is
a
<a class="tref internalDFN" title="literal" href="#dfn-literal">
literal
</a>
with
an
associated
<a class="tref internalDFN" title="iri" href="#dfn-iri">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
which
indicates
the
literal's
datatype.
See
<cite>
<a href="http://www.w3.org/TR/rdf11-concepts/#dfn-typed-literal">
languaged-tagged
literal
</a>
</cite>
in
[
<cite>
<a class="bibref" rel="biblioentry" href="#bib-RDF-CONCEPTS">
RDF-CONCEPTS
</a>
</cite>
].
</dd>
</dl>
</div>
<div id="context-processing" class="section">
<h3 id="context">
<span class="secno">
4.2
</span>
Context
Processing
</h3>
<p>
Processing
of
JSON-LD
data
structure
is
managed
recursively.
During
processing,
each
rule
is
applied
using
information
provided
by
the
<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
active
context
</a>.
Processing
begins
by
pushing
a
new
<a class="tref internalDFN" title="processor_state" href="#dfn-processor_state">
processor
state
</a>
onto
the
<a class="tref internalDFN" title="processor_state" href="#dfn-processor_state">
processor
state
</a>
stack
and
initializing
the
<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
active
context
</a>
with
the
<a class="tref internalDFN" title="initial_context" href="#dfn-initial_context">
initial
context
</a>.
If
a
<a class="tref internalDFN" title="local_context" href="#dfn-local_context">
local
context
</a>
is
encountered,
information
from
the
<a class="tref internalDFN" title="local_context" href="#dfn-local_context">
local
context
</a>
is
merged
into
the
<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
active
context
</a>.
</p>
<p>
The
<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
active
context
</a>
is
used
for
expanding
properties
and
values
of
a
<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
JSON
object
</a>
(or
elements
of
an
array)
using
a
<dfn title="term_mapping" id="dfn-term_mapping">
term
mapping
</dfn>.
It
is
also
used
to
maintain
<dfn title="coercion_mapping" id="dfn-coercion_mapping">
coercion
mapping
</dfn>
s
from
terms
to
datatypes,
<dfn title="language_mapping" id="dfn-language_mapping">
language
mapping
</dfn>
s
from
terms
to
language
codes,
and
<dfn title="list_mapping" id="dfn-list_mapping">
list
mapping
</dfn>
s
and
<dfn title="set_mapping" id="dfn-set_mapping">
set
mapping
</dfn>
s
for
terms.
Processors
<em class="rfc2119" title="must">
must
</em>
use
the
lexical
form
of
the
property
when
creating
a
mapping,
as
lookup
is
performed
on
lexical
forms,
not
expanded
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
representations.
</p>
<p>
A
<a class="tref internalDFN" title="local_context" href="#dfn-local_context">
local
context
</a>
is
identified
within
a
<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
JSON
object
</a>
having
a
<code>
@context
</code>
property
with
a
<a class="tref internalDFN" title="string" href="#dfn-string">
string
</a>,
<a class="tref internalDFN" title="array" href="#dfn-array">
array
</a>
or
a
<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
JSON
object
</a>
value.
When
processing
a
<a class="tref internalDFN" title="local_context" href="#dfn-local_context">
local
context
</a>,
special
processing
rules
apply:
</p>
<ol class="algorithm">
<li>
Create
a
new,
empty
<a class="tref internalDFN" title="local_context" href="#dfn-local_context">
local
context
</a>.
</li>
<li>
Let
<em>
context
</em>
be
the
value
of
<code>
@context
</code>
<ol class="algorithm">
<li id="process-context">
If
<em>
context
</em>
equals
<a class="tref internalDFN" title="null" href="#dfn-null">
null
</a>,
reset
the
<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
active
context
</a>
to
the
<a class="tref internalDFN" title="initial_context" href="#dfn-initial_context">
initial
context
</a>.
</li>
<li>
If
<em>
context
</em>
is
an
<a class="tref internalDFN" title="array" href="#dfn-array">
array
</a>,
process
each
element
as
<em>
context
</em>
in
order
by
starting
at
<a href="#process-context">
Step
2.1
</a>.
</li>
<li>
If
<em>
context
</em>
is
a
<a class="tref internalDFN" title="string" href="#dfn-string">
string
</a>,
it
<em class="rfc2119" title="must">
must
</em>
have
a
lexical
form
of
<a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">
absolute
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>.
<ol class="algorithm">
<li>
Dereference
<em>
context
</em>.
</li>
<li>
If
the
resulting
document
is
a
JSON
document,
extract
the
top-level
<code>
@context
</code>
element
using
the
JSON
Pointer
&quot;/@context&quot;
as
described
in
[
<cite>
<a class="bibref" rel="biblioentry" href="#bib-JSON-POINTER">
JSON-POINTER
</a>
</cite>
].
Set
<em>
context
</em>
to
the
extracted
content
and
process
it
by
starting
at
<a href="#process-context">
Step
2.1
</a>.
</li>
</ol>
</li>
<li>
If
<em>
context
</em>
is
a
<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
JSON
object
</a>,
perform
the
following
steps:
<ol class="algorithm">
<li>
If
<em>
context
</em>
has
a
<code>
@language
</code>
property,
it
<em class="rfc2119" title="must">
must
</em>
have
a
value
of
a
simple
<a class="tref internalDFN" title="string" href="#dfn-string">
string
</a>
or
<a class="tref internalDFN" title="null" href="#dfn-null">
null
</a>.
Add
the
language
to
the
<a class="tref internalDFN" title="local_context" href="#dfn-local_context">
local
context
</a>.
</li>
<li id="object-context">
Otherwise,
for
each
property
in
<em>
context
</em>
perform
the
following
steps:
<ol class="algorithm">
<li>
If
the
property's
value
is
a
simple
<a class="tref internalDFN" title="string" href="#dfn-string">
string
</a>,
determine
the
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
mapping
value
by
performing
<a href="#iri-expansion">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
Expansion
</a>
on
the
associated
value.
If
the
result
of
the
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
mapping
is
an
<a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">
absolute
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>,
merge
the
property
into
the
<a class="tref internalDFN" title="local_context" href="#dfn-local_context">
local
context
</a>
<a class="tref internalDFN" title="term_mapping" href="#dfn-term_mapping">
term
mapping
</a>,
unless
the
property
is
a
JSON-LD
<a class="tref internalDFN" title="keyword" href="#dfn-keyword">
keyword
</a>,
in
which
case
throw
an
exception.
</li>
<li>
Otherwise,
if
the
property's
value
is
<a class="tref internalDFN" title="null" href="#dfn-null">
null
</a>
remove
mapping,
coercion,
container
and
language
information
associated
with
property
from
the
<a class="tref internalDFN" title="local_context" href="#dfn-local_context">
local
context
</a>.
</li>
<li>
Otherwise,
the
<em>
property
</em>
's
<em>
value
</em>
<em class="rfc2119" title="must">
must
</em>
be
a
<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
JSON
object
</a>.
<ol class="algorithm">
<li>
If
the
<em>
property
</em>
is
a
JSON-LD
<a class="tref internalDFN" title="keyword" href="#dfn-keyword">
keyword
</a>
and
the
value
has
<code>
@id
</code>,
<code>
@language
</code>
or
<code>
@type
</code>
properties,
throw
an
exception.
<div class="issue">
<div class="issue-title">
<span>
Issue
5
</span>
</div>
<div class="">
Undecided
if
<code>
@type
</code>
or
<code>
@graph
</code>
can
take
a
<code>
@container
</code>
with
<code>
@set
</code>.
</div>
</div>
</li>
<li>
If
the
<em>
property
</em>
has
the
form
of
<a class="tref internalDFN" title="term" href="#dfn-term">
term
</a>,
its
<em>
value
</em>
<em class="rfc2119" title="must">
must
</em>
have
an
<code>
@id
</code>
property
with
a
string
value
which
<em class="rfc2119" title="must">
must
</em>
have
the
form
of
a
<a class="tref internalDFN" title="term" href="#dfn-term">
term
</a>,
<a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">
compact
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>,
or
<a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">
absolute
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>.
Determine
the
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
mapping
by
performing
<a href="#iri-expansion">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
Expansion
</a>
on
the
associated
value.
If
the
result
of
the
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
mapping
is
an
<a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">
absolute
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>,
merge
the
<em>
property
</em>
into
the
<a class="tref internalDFN" title="local_context" href="#dfn-local_context">
local
context
</a>
<a class="tref internalDFN" title="term_mapping" href="#dfn-term_mapping">
term
mapping
</a>.
</li>
<li>
If
the
<em>
property
</em>
has
the
form
of
of
a
<a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">
compact
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
or
<a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">
absolute
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>,
the
<em>
value
</em>
<em class="rfc2119" title="may">
may
</em>
have
a
<code>
@id
</code>
property
with
a
string
value
which
<em class="rfc2119" title="must">
must
</em>
have
the
form
of
a
<a class="tref internalDFN" title="term" href="#dfn-term">
term
</a>,
<a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">
compact
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>,
or
absolute
<a class="tref internalDFN" title="iri" href="#dfn-iri">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>.
Determine
the
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
mapping
by
performing
<a href="#iri-expansion">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
Expansion
</a>
on
the
associated
value.
If
the
result
of
the
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
mapping
is
an
<a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">
absolute
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>,
merge
the
<em>
property
</em>
into
the
<a class="tref internalDFN" title="local_context" href="#dfn-local_context">
local
context
</a>
<a class="tref internalDFN" title="term_mapping" href="#dfn-term_mapping">
term
mapping
</a>.
</li>
<li>
If
the
<em>
value
</em>
has
a
<code>
@type
</code>
property,
its
value
<em class="rfc2119" title="must">
must
</em>
have
the
form
of
a
<a class="tref internalDFN" title="term" href="#dfn-term">
term
</a>,
<a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">
compact
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>,
<a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">
absolute
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>,
or
the
<a class="tref internalDFN" title="keyword" href="#dfn-keyword">
keyword
</a>
<code>
@id
</code>.
Determine
the
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
by
performing
<a href="#iri-expansion">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
Expansion
</a>
on
the
associated
value.
If
the
result
of
the
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
mapping
is
an
<a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">
absolute
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
or
<code>
@id
</code>,
merge
into
the
<a class="tref internalDFN" title="local_context" href="#dfn-local_context">
local
context
</a>
<a class="tref internalDFN" title="coercion_mapping" href="#dfn-coercion_mapping">
coercion
mapping
</a>
using
the
lexical
value
of
the
<em>
property
</em>.
</li>
<li>
If
the
<em>
value
</em>
has
a
<code>
@container
</code>
property,
its
value
<em class="rfc2119" title="must">
must
</em>
be
<code>
@list
</code>
or
<code>
@set
</code>.
Merge
the
<a class="tref internalDFN" title="list_mapping" href="#dfn-list_mapping">
list
mapping
</a>
or
<a class="tref internalDFN" title="set_mapping" href="#dfn-set_mapping">
set
mapping
</a>
into
the
<a class="tref internalDFN" title="local_context" href="#dfn-local_context">
local
context
</a>
using
the
lexical
value
of
the
<em>
property
</em>.
</li>
<li>
If
the
<em>
value
</em>
has
a
<code>
@language
</code>
property
but
no
<code>
@type
</code>
property,
the
value
of
the
<code>
@language
</code>
property
<em class="rfc2119" title="must">
must
</em>
be
a
<a class="tref internalDFN" title="string" href="#dfn-string">
string
</a>
or
<a class="tref internalDFN" title="null" href="#dfn-null">
null
</a>.
Merge
the
<a class="tref internalDFN" title="language_mapping" href="#dfn-language_mapping">
language
mapping
</a>
into
the
<a class="tref internalDFN" title="local_context" href="#dfn-local_context">
local
context
</a>
using
the
lexical
value
of
the
<em>
property
</em>.
</li>
</ol>
</li>
<li>
Merge
the
<a class="tref internalDFN" title="local_context" href="#dfn-local_context">
local
context
</a>
into
the
<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
active
context
</a>.
</li>
<li>
Repeat
<a href="#object-context">
Step
2.4.2
</a>
until
no
entries
are
added
to
the
<a class="tref internalDFN" title="local_context" href="#dfn-local_context">
local
context
</a>.
</li>
</ol>
</li>
</ol>
</li>
</ol>
</li>
</ol>
<div class="note">
<div class="note-title">
<span>
Note
</span>
</div>
<p class="">
It
can
be
difficult
to
distinguish
between
a
<a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">
compact
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
and
an
<a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">
absolute
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>,
as
a
<a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">
compact
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
may
seem
to
be
a
valid
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
<em>
scheme
</em>.
When
performing
repeated
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
expansion,
a
term
used
as
a
prefix
may
not
have
a
valid
mapping
due
to
dependencies
in
resolving
term
definitions.
By
continuing
<a href="#object-context">
Step
2.3.2
</a>
until
no
changes
are
made,
mappings
to
IRIs
created
using
an
undefined
term
prefix
will
eventually
resolve
to
<a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">
absolute
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
s.
</p>
</div>
<div class="issue">
<div class="issue-title">
<span>
Issue
6
</span>
</div>
<p class="">
<a href="https://github.com/json-ld/json-ld.org/issues/43">
Issue
43
</a>
concerns
performing
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
expansion
in
the
key
position
of
a
context
definition.
</p>
</div>
</div>
<div id="iri-expansion" class="section">
<h3>
<span class="secno">
4.3
</span>
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
Expansion
</h3>
<p>
Keys
and
some
values
are
evaluated
to
produce
an
<a class="tref internalDFN" title="iri" href="#dfn-iri">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>.
This
section
defines
an
algorithm
for
transforming
a
value
representing
an
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
into
an
actual
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>.
</p>
<p>
<a class="tref internalDFN" title="iri" href="#dfn-iri">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
s
may
be
represented
as
an
<a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">
absolute
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>,
a
<a class="tref internalDFN" title="term" href="#dfn-term">
term
</a>
or
a
<a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">
compact
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>.
</p>
<p>
An
<dfn title="absolute_iri" id="dfn-absolute_iri">
absolute
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</dfn>
is
defined
in
[
<cite>
<a class="bibref" rel="biblioentry" href="#bib-RFC3987">
RFC3987
</a>
</cite>
]
containing
a
<em>
scheme
</em>
along
with
<em>
path
</em>
and
optional
<em>
query
</em>
and
fragment
segments.
A
<dfn title="relative_iri" id="dfn-relative_iri">
relative
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</dfn>
is
an
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
that
is
relative
some
other
<a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">
absolute
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
;
in
the
case
of
JSON-LD
this
is
the
base
location
of
the
document.
</p>
<p>
The
algorithm
for
generating
an
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
is:
</p>
<ol class="algorithm">
<li>
If
the
<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
active
context
</a>
contains
a
<a class="tref internalDFN" title="term" href="#dfn-term">
term
</a>
mapping
for
the
value
using
a
case-sensitive
comparison,
use
the
mapped
value
as
an
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>.
</li>
<li>
Otherwise,
split
the
value
into
a
<em>
prefix
</em>
and
<em>
suffix
</em>
from
the
first
occurrence
of
':'.
</li>
<li>
If
the
prefix
is
a
'_'
(underscore),
the
value
represents
a
named
<a class="tref internalDFN" title="blank_node" href="#dfn-blank_node">
blank
node
</a>.
</li>
<li>
If
the
<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
active
context
</a>
contains
a
<a class="tref internalDFN" title="term" href="#dfn-term">
term
</a>
mapping
for
<em>
prefix
</em>
using
a
case-sensitive
comparison,
and
<em>
suffix
</em>
does
not
does
not
begin
with
'//'
(i.e.,
it
does
not
match
a
<em>
hier-part
</em>
including
<em>
authority
</em>
(as
defined
in
[
<cite>
<a class="bibref" rel="biblioentry" href="#bib-RFC3986">
RFC3986
</a>
</cite>
]),
generate
an
<a class="tref internalDFN" title="iri" href="#dfn-iri">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
by
prepending
the
mapped
prefix
to
the
(possibly
empty)
suffix
using
textual
concatenation.
Note
that
an
empty
suffix
and
no
suffix
(meaning
the
value
contains
no
':'
string
at
all)
are
treated
equivalently.
</li>
<li>
Otherwise,
use
the
value
directly
as
an
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>.
</li>
</ol>
<p>
</p>
<div class="note">
<div class="note-title">
<span>
Note
</span>
</div>
<p class="">
Previous
versions
of
this
specification
used
<code>
@base
</code>
and
<code>
@vocab
</code>
to
define
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
prefixes
used
to
resolve
<a class="tref internalDFN" title="relative_iri" href="#dfn-relative_iri">
relative
IRIs
</a>.
It
was
determined
that
this
added
too
much
complexity,
but
the
issue
can
be
re-examined
in
the
future
based
on
community
input.
</p>
</div>
</div>
<div id="iri-compaction" class="section">
<h3>
<span class="secno">
4.4
</span>
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
Compaction
</h3>
<p>
Some
keys
and
values
are
expressed
using
<a class="tref internalDFN" title="iri" href="#dfn-iri">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
s.
This
section
defines
an
algorithm
for
transforming
an
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
(
<em>
iri
</em>
)
to
a
<a class="tref internalDFN" title="term" href="#dfn-term">
term
</a>
or
<a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">
compact
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
using
the
<a class="tref internalDFN" title="term" href="#dfn-term">
term
</a>
s
specified
in
the
<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
active
context
</a>
using
an
optional
<em>
value
</em>.
</p>
<div id="iri-compaction-algorithm" class="section">
<h4>
<span class="secno">
4.4.1
</span>
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
Compaction
Algorithm
</h4>
<p>
The
algorithm
for
generating
a
<a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">
compact
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
is:
</p>
<ol class="algorithm">
<li>
Create
an
empty
list
of
terms
<em>
terms
</em>
that
will
be
populated
with
<a class="tref internalDFN" title="term" href="#dfn-term">
term
</a>
s
that
are
ranked
according
to
how
closely
they
match
<em>
value
</em>.
Initialize
<em>
highest
rank
</em>
to
<code>
0
</code>,
and
set
a
flag
<em>
list
container
</em>
to
<code>
false
</code>.
</li>
<li>
For
each
<em>
term
</em>
in
the
<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
active
context
</a>:
<ol class="algorithm">
<li>
If
the
<em>
term
</em>
's
<a class="tref internalDFN" title="iri" href="#dfn-iri">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
is
not
a
complete
match
against
<em>
iri
</em>,
continue
to
the
next
<em>
term
</em>.
</li>
<li>
If
<em>
value
</em>
is
a
<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
JSON
object
</a>
containing
only
the
property
<code>
@list
</code>:
<ol class="algorithm">
<li>
If
<em>
term
</em>
has
a
<code>
@container
</code>
set
to
<code>
@set
</code>,
continue
to
the
next
<em>
term
</em>.
</li>
<li>
If
<em>
list
container
</em>
is
<code>
true
</code>
and
<em>
term
</em>
does
not
have
a
<code>
container
</code>
set
to
<code>
@list
</code>,
continue
to
the
next
<em>
term
</em>.
</li>
</ol>
</li>
<li>
Otherwise,
if
<em>
term
</em>
has
a
<code>
container
</code>
set
to
<code>
@list
</code>,
continue
to
the
next
<em>
term
</em>.
</li>
<li>
Set
<em>
rank
</em>
to
the
<a class="tref internalDFN" title="term_rank" href="#dfn-term_rank">
term
rank
</a>
of
<em>
value
</em>
by
passing
passing
<em>
term
</em>,
<em>
value
</em>,
and
<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
active
context
</a>
to
the
<a href="#term-rank-algorithm">
Term
Rank
Algorithm
</a>.
</li>
<li>
If
<em>
rank
</em>
is
greater
than
<code>
0
</code>:
<ol class="algorithm">
<li>
If
<em>
term
</em>
has
a
<code>
container
</code>
set
to
<code>
@set
</code>,
then
add
<code>
1
</code>
to
<em>
rank
</em>.
</li>
<li>
If
<em>
value
</em>
is
a
<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
JSON
object
</a>
containing
only
the
property
<code>
@list
</code>
and
<em>
list
container
</em>
is
<code>
false
</code>
and
<em>
term
</em>
has
a
<code>
container
</code>
set
to
<code>
@list
</code>,
then
set
<em>
list
container
</em>
to
<code>
true
</code>,
clear
<em>
terms
</em>,
set
<em>
highest
rank
</em>
to
<em>
rank
</em>,
and
add
<em>
term
</em>
to
<em>
terms
</em>.
</li>
<li>
Otherwise,
if
<em>
rank
</em>
is
greater
than
or
equal
to
<em>
highest
rank
</em>:
<ol class="algorithm">
<li>
If
<em>
rank
</em>
is
greater
than
<em>
highest
rank
</em>,
clear
<em>
terms
</em>
and
set
<em>
highest
rank
</em>
to
<em>
rank
</em>.
</li>
<li>
Add
<em>
term
</em>
to
<em>
terms
</em>.
</li>
</ol>
</li>
</ol>
</li>
</ol>
</li>
<li>
If
<em>
terms
</em>
is
empty,
add
a
<a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">
compact
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
representation
of
<em>
iri
</em>
for
each
<a class="tref internalDFN" title="term" href="#dfn-term">
term
</a>
in
the
<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
active
context
</a>
which
maps
to
an
<a class="tref internalDFN" title="iri" href="#dfn-iri">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
which
is
a
prefix
for
<em>
iri
</em>
where
the
resulting
<a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">
compact
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
is
not
a
<a class="tref internalDFN" title="term" href="#dfn-term">
term
</a>
in
the
<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
active
context
</a>.
The
resulting
<a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">
compact
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
is
the
<a class="tref internalDFN" title="term" href="#dfn-term">
term
</a>
associated
with
the
partially
matched
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
in
the
<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
active
context
</a>
concatenated
with
a
colon
(:)
character
and
the
unmatched
part
of
<em>
iri
</em>.
</li>
<li>
If
<em>
terms
</em>
is
empty,
return
<em>
iri
</em>.
</li>
<li>
Otherwise,
return
the
shortest
and
lexicographically
least
value
in
<em>
terms
</em>.
</li>
</ol>
<p>
</p>
</div>
<div id="term-rank-algorithm" class="section">
<h4>
<span class="secno">
4.4.2
</span>
Term
Rank
Algorithm
</h4>
<p>
When
selecting
among
multiple
possible
terms
for
a
given
property,
it
may
be
that
multiple
<a class="tref internalDFN" title="term" href="#dfn-term">
terms
</a>
are
defined
with
the
same
<a class="tref internalDFN" title="iri" href="#dfn-iri">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>,
but
differ
in
<code>
@type
</code>,
<code>
@container
</code>
or
<code>
@language
</code>.
The
purpose
of
this
algorithm
is
to
take
a
<a class="tref internalDFN" title="term" href="#dfn-term">
term
</a>
and
a
value
and
give
it
a
<dfn title="term_rank" id="dfn-term_rank">
term
rank
</dfn>.
The
selection
can
then
be
based,
partly,
on
the
term
having
the
highest
<a class="tref internalDFN" title="term_rank" href="#dfn-term_rank">
term
rank
</a>.
</p>
<p>
Given
a
<a class="tref internalDFN" title="term" href="#dfn-term">
term
</a>
<em>
term
</em>,
<em>
value
</em>,
and
<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
active
context
</a>
determine
the
<a class="tref internalDFN" title="term_rank" href="#dfn-term_rank">
term
rank
</a>
using
the
following
steps:
</p>
<ol class="algorithm">
<li>
If
<em>
value
</em>
is
<a class="tref internalDFN" title="null" href="#dfn-null">
null
</a>,
<a class="tref internalDFN" title="term_rank" href="#dfn-term_rank">
term
rank
</a>
is
<code>
3
</code>.
</li>
<li>
Otherwise,
if
<em>
value
</em>
is
a
<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
JSON
object
</a>
containing
only
the
property
<code>
@list
</code>:
<ol class="algorithm">
<li>
If
the
<code>
@list
</code>
property
is
an
empty
array,
if
<em>
term
</em>
has
<code>
@container
</code>
set
to
<code>
@list
</code>,
<a class="tref internalDFN" title="term_rank" href="#dfn-term_rank">
term
rank
</a>
is
<code>
1
</code>,
otherwise
<code>
0
</code>.
</li>
<li>
Otherwise,
return
the
sum
of
the
<a class="tref internalDFN" title="term_rank" href="#dfn-term_rank">
term
rank
</a>
s
for
every
entry
in
the
list.
</li>
</ol>
</li>
<li>
Otherwise,
<em>
value
</em>
<em class="rfc2119" title="must">
must
</em>
be
a
<a class="tref internalDFN" title="subject_definition" href="#dfn-subject_definition">
subject
definition
</a>,
<a class="tref internalDFN" title="subject_reference" href="#dfn-subject_reference">
subject
reference
</a>,
or
a
<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
JSON
object
</a>
having
a
<code>
@value
</code>.
<ol class="algorithm">
<li>
If
<em>
value
</em>
has
a
<code>
@value
</code>
property:
<ol class="algorithm">
<li>
If
<em>
value
</em>
has
a
<code>
@type
</code>
property
matching
a
<code>
@type
</code>
coercion
for
<em>
term
</em>,
<a class="tref internalDFN" title="term_rank" href="#dfn-term_rank">
term
rank
</a>
is
<code>
3
</code>,
otherwise
if
<em>
term
</em>
has
no
<code>
@type
</code>
coercion
and
no
<code>
@language
</code>,
<a class="tref internalDFN" title="term_rank" href="#dfn-term_rank">
term
rank
</a>
is
<code>
1
</code>,
otherwise
<code>
0
</code>.
</li>
<li>
Otherwise,
if
<code>
@value
</code>
is
not
a
<a class="tref internalDFN" title="string" href="#dfn-string">
string
</a>,
if
<em>
term
</em>
has
no
<code>
@type
</code>
or
<code>
@language
</code>
it
is
<code>
2
</code>,
otherwise
<code>
1
</code>.
</li>
<li>
Otherwise,
if
<em>
value
</em>
has
no
<code>
@language
</code>
property,
if
<em>
term
</em>
has
<code>
@language
</code>
<a class="tref internalDFN" title="null" href="#dfn-null">
null
</a>,
or
<em>
term
</em>
has
no
<code>
@type
</code>
or
<code>
@language
</code>
and
the
<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
active
context
</a>
has
no
<code>
@language
</code>,
<a class="tref internalDFN" title="term_rank" href="#dfn-term_rank">
term
rank
</a>
is
<code>
3
</code>,
otherwise
<code>
0
</code>.
</li>
<li>
Otherwise,
if
<em>
value
</em>
has
a
<code>
@language
</code>
property
matching
a
<code>
@language
</code>
definition
for
<em>
term
</em>
(or
<em>
term
</em>
has
no
<code>
@type
</code>
or
<code>
@language
</code>
definition
and
<code>
@language
</code>
in
the
<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
active
context
</a>
matches
the
<em>
value
</em>
<code>
@language
</code>
),
<a class="tref internalDFN" title="term_rank" href="#dfn-term_rank">
term
rank
</a>
is
<code>
3
</code>,
otherwise
if
<em>
term
</em>
has
no
<code>
@type
</code>
coercion
and
no
<code>
@language
</code>,
<a class="tref internalDFN" title="term_rank" href="#dfn-term_rank">
term
rank
</a>
is
<code>
1
</code>,
otherwise
<code>
0
</code>.
</li>
</ol>
</li>
<li>
Otherwise,
if
<em>
term
</em>
has
<code>
@type
</code>
coerced
to
<code>
@id
</code>,
<a class="tref internalDFN" title="term_rank" href="#dfn-term_rank">
term
rank
</a>
is
<code>
3
</code>,
otherwise
if
<em>
term
</em>
has
no
<code>
@type
</code>
coercion
and
no
<code>
@language
</code>,
<a class="tref internalDFN" title="term_rank" href="#dfn-term_rank">
term
rank
</a>
is
<code>
1
</code>,
otherwise
<code>
0
</code>.
</li>
</ol>
</li>
<li>
Return
<a class="tref internalDFN" title="term_rank" href="#dfn-term_rank">
term
rank
</a>.
</li>
</ol>
</div>
</div>
<div id="value-expansion" class="section">
<h3>
<span class="secno">
4.5
</span>
Value
Expansion
</h3>
<p>
Some
values
in
JSON-LD
can
be
expressed
in
a
compact
form.
These
values
are
required
to
be
expanded
at
times
when
processing
JSON-LD
documents.
</p>
<p>
The
algorithm
for
expanding
a
<em>
value
</em>
takes
an
<a class="tref internalDFN" title="active_property" href="#dfn-active_property">
active
property
</a>
and
<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
active
context
</a>.
It
is
implemented
as
follows:
</p>
<ol class="algorithm">
<li>
If
<em>
value
</em>
is
<a class="tref internalDFN" title="null" href="#dfn-null">
null
</a>,
the
<em>
value
</em>
is
already
expanded.
</li>
<li>
If
<a class="tref internalDFN" title="active_property" href="#dfn-active_property">
active
property
</a>
is
<code>
@graph
</code>
or
the
target
of
an
<code>
@id
</code>
coercion,
expand
the
value
into
an
object
with
a
key-value
pair
where
the
key
is
<code>
@id
</code>
and
the
value
is
the
expanded
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
according
to
the
<a href="#iri-expansion">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
Expansion
</a>
rules.
</li>
<li>
Otherwise,
if
<a class="tref internalDFN" title="active_property" href="#dfn-active_property">
active
property
</a>
is
not
a
<a class="tref internalDFN" title="keyword" href="#dfn-keyword">
keyword
</a>,
then
expand
<em>
value
</em>
into
an
object:
<ol class="algorithm">
<li>
Set
the
first
key-value
pair
to
<code>
@value
</code>
and
the
unexpanded
<em>
value
</em>.
</li>
<li>
If
the
<a class="tref internalDFN" title="active_property" href="#dfn-active_property">
active
property
</a>
is
the
target
of
typed
literal
coercion,
set
the
second
key-value
pair
to
<code>
@type
</code>
and
the
associated
coercion
datatype
expanded
according
to
the
<a href="#iri-expansion">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
Expansion
</a>
rules.
</li>
<li>
Otherwise,
if
the
<a class="tref internalDFN" title="active_property" href="#dfn-active_property">
active
property
</a>
is
the
target
of
language
tagging,
set
the
second
key-value
pair
to
<code>
@language
</code>
and
value
of
the
language
tagging
from
the
<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
active
context
</a>.
</li>
</ol>
</li>
<li>
Otherwise,
<em>
value
</em>
is
already
expanded.
</li>
</ol>
</div>
<div id="value-compaction" class="section">
<h3>
<span class="secno">
4.6
</span>
Value
Compaction
</h3>
<p>
Some
values,
such
as
<a class="tref internalDFN" title="iri" href="#dfn-iri">
IRIs
</a>
and
<a class="tref internalDFN" title="typed_literal" href="#dfn-typed_literal">
typed
literals
</a>,
may
be
expressed
in
an
expanded
form
in
JSON-LD.
These
values
are
required
to
be
compacted
at
times
when
processing
JSON-LD
documents.
</p>
<p>
The
algorithm
for
compacting
an
expanded
value
<em>
value
</em>
takes
an
<a class="tref internalDFN" title="active_property" href="#dfn-active_property">
active
property
</a>
and
<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
active
context
</a>.
It
is
implemented
as
follows:
</p>
<ol class="algorithm">
<li>
If
<em>
value
</em>
only
has
one
property
and
the
<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
active
context
</a>
has
no
default
language,
then
the
compacted
value
is
the
value
of
<code>
@value
</code>.
</li>
<li>
Otherwise,
if
<a class="tref internalDFN" title="active_property" href="#dfn-active_property">
active
property
</a>
is
<code>
@graph
</code>,
the
compacted
value
is
the
value
associated
with
the
<code>
@id
</code>
key,
processed
according
to
the
<a href="#iri-compaction">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
Compaction
</a>
steps.
</li>
<li>
Otherwise,
if
the
<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
active
context
</a>
contains
a
coercion
target
for
the
key
that
matches
the
expression
of
the
value,
compact
the
value
using
the
following
steps:
<ol class="algorithm">
<li>
If
the
coercion
target
is
an
<code>
@id
</code>,
the
compacted
value
is
the
value
associated
with
the
<code>
@id
</code>
key,
processed
according
to
the
<a href="#iri-compaction">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
Compaction
</a>
steps.
</li>
<li>
If
the
coercion
target
is
a
<a class="tref internalDFN" title="typed_literal" href="#dfn-typed_literal">
typed
literal
</a>,
the
compacted
value
is
the
value
associated
with
the
<code>
@value
</code>
key.
</li>
</ol>
</li>
<li>
Otherwise,
if
<em>
value
</em>
contains
an
<code>
@id
</code>
key,
the
compacted
value
is
<em>
value
</em>
with
the
value
of
<code>
@id
</code>
processed
according
to
the
<a href="#iri-compaction">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
Compaction
</a>
steps.
</li>
<li>
Otherwise,
if
the
<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
active
context
</a>
contains
a
<code>
@language
</code>,
which
matches
the
<code>
@language
</code>
of
the
value,
or
the
value
has
only
a
<code>
@value
</code>
key,
the
compacted
value
is
the
value
associated
with
the
<code>
@value
</code>
key.
</li>
<li>
Otherwise,
if
the
value
contains
a
<code>
@type
</code>
key,
the
compacted
value
is
<em>
value
</em>
with
the
<code>
@type
</code>
value
processed
according
to
the
<a href="#iri-compaction">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
Compaction
</a>
steps.
</li>
<li>
Otherwise,
the
value
is
not
modified.
</li>
</ol>
</div>
<div id="expansion-1" class="section">
<h3>
<span class="secno">
4.7
</span>
Expansion
</h3>
<p>
Expansion
is
the
process
of
taking
a
JSON-LD
document
and
applying
a
context
such
that
all
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>,
datatypes,
and
literal
values
are
expanded
so
that
the
context
is
no
longer
necessary.
JSON-LD
document
expansion
is
typically
used
as
a
part
of
other
JSON-LD
API
methods.
</p>
<p>
For
example,
assume
the
following
JSON-LD
input
document:
</p>
<div class="example"><div class="example-title"><span>Example 13</span></div><pre class="example">{
   &quot;@context&quot;:
   {
      &quot;name&quot;: &quot;http://xmlns.com/foaf/0.1/name&quot;,
      &quot;homepage&quot;: {
        &quot;@id&quot;: &quot;http://xmlns.com/foaf/0.1/homepage&quot;,
        &quot;@type&quot;, &quot;@id&quot;
      }
   },
   &quot;name&quot;: &quot;Manu Sporny&quot;,
   &quot;homepage&quot;: &quot;http://manu.sporny.org/&quot;
}
</pre>
</div>
<p>
Running
the
JSON-LD
Expansion
algorithm
against
the
JSON-LD
input
document
provided
above
would
result
in
the
following
output:
</p>
<div class="example"><div class="example-title"><span>Example 14</span></div><pre class="example">{
   &quot;http://xmlns.com/foaf/0.1/name&quot;: &quot;Manu Sporny&quot;,
   &quot;http://xmlns.com/foaf/0.1/homepage&quot;: {
      &quot;@id&quot;: &quot;http://manu.sporny.org/&quot;
   }
}
</pre>
</div>
<div id="expansion-algorithm" class="section">
<h4>
<span class="secno">
4.7.1
</span>
Expansion
Algorithm
</h4>
<p>
The
algorithm
takes
three
input
variables:
an
<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
active
context
</a>,
an
<a class="tref internalDFN" title="active_property" href="#dfn-active_property">
active
property
</a>,
and
an
<em>
element
</em>
to
be
expanded.
To
begin,
the
<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
active
context
</a>
is
set
to
the
result
of
performing,
<a href="#context-processing">
Context
Processing
</a>
on
the
passed
<em>
context
</em>,
or
to
the
<a class="tref internalDFN" title="initial_context" href="#dfn-initial_context">
initial
context
</a>
if
<em>
context
</em>
is
<a class="tref internalDFN" title="null" href="#dfn-null">
null
</a>,
<a class="tref internalDFN" title="active_property" href="#dfn-active_property">
active
property
</a>
is
set
to
<a class="tref internalDFN" title="null" href="#dfn-null">
null
</a>,
and
<em>
element
</em>
is
set
to
the
<a class="tref internalDFN" title="json-ld_input" href="#dfn-json-ld_input">
JSON-LD
input
</a>.
</p>
<ol class="algorithm">
<li>
If
<em>
element
</em>
is
an
<a class="tref internalDFN" title="array" href="#dfn-array">
array
</a>,
process
each
entry
in
<em>
element
</em>
recursively
using
this
algorithm,
passing
copies
of
the
<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
active
context
</a>
and
<a class="tref internalDFN" title="active_property" href="#dfn-active_property">
active
property
</a>.
If
has
a
<code>
@container
</code>
set
to
<code>
@list
</code>
and
any
entry
in
<em>
element
</em>
is
an
<a class="tref internalDFN" title="array" href="#dfn-array">
array
</a>,
or
is
a
<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
JSON
object
</a>
containing
a
<code>
@list
</code>
property,
throw
an
exception,
as
lists
of
lists
are
not
allowed.
If
the
expanded
entry
is
null,
drop
it.
If
it's
an
array,
merge
its
entries
with
<em>
element
</em>
's
entries.
</li>
<li>
Otherwise,
if
<em>
element
</em>
is
an
object
<ol class="algorithm">
<li>
If
<em>
element
</em>
has
a
<code>
@context
</code>
property,
update
the
<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
active
context
</a>
according
to
the
steps
outlined
in
<a href="#context-processing">
Context
Processing
</a>
and
remove
the
<code>
@context
</code>
property.
</li>
<li>
Then,
proceed
and
process
each
<em>
property
</em>
and
<em>
value
</em>
in
<em>
element
</em>
as
follows:
<ol class="algorithm">
<li>
Remove
<em>
property
</em>
from
<em>
element
</em>,
expand
<em>
property
</em>
according
to
the
steps
outlined
in
<a href="#iri-expansion">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
Expansion
</a>.
Set
the
<a class="tref internalDFN" title="active_property" href="#dfn-active_property">
active
property
</a>
to
the
original
un-expanded
<em>
property
</em>
if
<em>
property
</em>
is
not
a
<a class="tref internalDFN" title="keyword" href="#dfn-keyword">
keyword
</a>.
</li>
<li>
If
<em>
property
</em>
does
not
expand
to
a
keyword
or
an
<a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">
absolute
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
(i.e.,
it
doesn't
contain
a
colon),
continue
with
the
next
property
from
<em>
element
</em>.
</li>
<li>
If
<em>
value
</em>
is
<a class="tref internalDFN" title="null" href="#dfn-null">
null
</a>
and
<em>
property
</em>
is
not
<code>
@value
</code>,
continue
with
the
next
property
from
<em>
element
</em>.
</li>
<li>
If
the
<em>
property
</em>
is
<code>
@id
</code>
the
<em>
value
</em>
<em class="rfc2119" title="must">
must
</em>
be
a
<a class="tref internalDFN" title="string" href="#dfn-string">
string
</a>.
Expand
the
<em>
value
</em>
according
to
<a href="#iri-expansion">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
Expansion
</a>.
</li>
<li>
Otherwise,
if
the
<em>
property
</em>
is
<code>
@type
</code>:
<ol class="algorithm">
<li>
If
<em>
value
</em>
is
a
<a class="tref internalDFN" title="string" href="#dfn-string">
string
</a>,
expand
according
to
<a href="#iri-expansion">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
Expansion
</a>.
</li>
<li>
Otherwise,
if
<em>
value
</em>
is
a
<a class="tref internalDFN" title="subject_reference" href="#dfn-subject_reference">
subject
reference
</a>,
the
expanded
value
is
the
result
of
performing
<a href="#iri-expansion">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
Expansion
</a>
on
the
value
of
<code>
@id
</code>.
</li>
<li>
Otherwise,
if
<em>
value
</em>
is
a
<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
JSON
Object
</a>,
it
must
be
empty
(used
for
<cite>
<a href="../json-ld-framing/#framing">
Framing
</a>
</cite>
).
</li>
<li>
Otherwise,
if
<em>
value
</em>
is
an
<a class="tref internalDFN" title="array" href="#dfn-array">
array
</a>,
all
elements
must
be
either
a
<a class="tref internalDFN" title="string" href="#dfn-string">
string
</a>
or
<a class="tref internalDFN" title="subject_reference" href="#dfn-subject_reference">
subject
reference
</a>.
Expand
<em>
value
</em>
for
each
of
its
entries
using
the
previous
three
steps.
</li>
</ol>
</li>
<li>
Otherwise,
if
the
<em>
property
</em>
is
<code>
@value
</code>
or
<code>
@language
</code>
the
<em>
value
</em>
<em class="rfc2119" title="must not">
must
not
</em>
be
a
<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
JSON
object
</a>
or
an
<a class="tref internalDFN" title="array" href="#dfn-array">
array
</a>.
</li>
<li>
Otherwise,
if
the
<em>
property
</em>
is
<code>
@list
</code>
or
<code>
@set
</code>
expand
<em>
value
</em>
recursively
using
this
algorithm,
passing
copies
of
the
<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
active
context
</a>
and
<em>
active
property
</em>.
If
the
expanded
<em>
value
</em>
is
not
an
<a class="tref internalDFN" title="array" href="#dfn-array">
array
</a>,
convert
it
to
an
<a class="tref internalDFN" title="array" href="#dfn-array">
array
</a>.
If
<em>
property
</em>
is
<code>
@list
</code>
and
any
entry
in
<em>
value
</em>
is
a
<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
JSON
object
</a>
containing
an
<code>
@list
</code>
property,
throw
an
exception,
as
lists
of
lists
are
not
supported.
</li>
<li>
Otherwise,
expand
<em>
value
</em>
recursively
using
this
algorithm,
passing
copies
of
the
<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
active
context
</a>
and
<a class="tref internalDFN" title="active_property" href="#dfn-active_property">
active
property
</a>.
</li>
<li>
If
<em>
property
</em>
is
not
a
keyword
and
<a class="tref internalDFN" title="active_property" href="#dfn-active_property">
active
property
</a>
has
a
<code>
@container
</code>
<code>
@list
</code>
and
the
expanded
<em>
value
</em>
is
not
<a class="tref internalDFN" title="null" href="#dfn-null">
null
</a>,
convert
<em>
value
</em>
to
an
<a class="tref internalDFN" title="object" href="#dfn-object">
object
</a>
with
an
<code>
@list
</code>
property
whose
value
is
set
to
<em>
value
</em>
(unless
<em>
value
</em>
is
already
in
that
form).
</li>
<li>
Convert
<em>
value
</em>
to
<a class="tref internalDFN" title="array" href="#dfn-array">
array
</a>
form
unless
<em>
value
</em>
is
<a class="tref internalDFN" title="null" href="#dfn-null">
null
</a>
or
<em>
property
</em>
is
<code>
@id
</code>,
<code>
@type
</code>,
<code>
@value
</code>,
or
<code>
@language
</code>.
</li>
<li>
If
<em>
value
</em>
is
not
<a class="tref internalDFN" title="null" href="#dfn-null">
null
</a>,
either
merge
<em>
value
</em>
into
an
existing
<em>
property
</em>
property
of
<em>
element
</em>
or
create
a
new
<em>
property
</em>
property
with
<em>
value
</em>
as
value.
</li>
</ol>
</li>
<li>
If
the
processed
<em>
element
</em>
has
an
<code>
@value
</code>
property
<ol class="algorithm">
<li>
<em>
element
</em>
<em class="rfc2119" title="must not">
must
not
</em>
have
more
than
one
other
property,
which
can
either
be
<code>
@language
</code>
or
<code>
@type
</code>
with
a
<a class="tref internalDFN" title="string" href="#dfn-string">
string
</a>
value.
</li>
<li>
if
the
value
of
<code>
@value
</code>
equals
<a class="tref internalDFN" title="null" href="#dfn-null">
null
</a>,
replace
<em>
element
</em>
with
the
value
of
<code>
@value
</code>.
</li>
</ol>
</li>
<li>
Otherwise,
if
<em>
element
</em>
has
an
<code>
@type
</code>
property
and
its
value
is
not
in
the
form
of
an
<a class="tref internalDFN" title="array" href="#dfn-array">
array
</a>,
convert
it
to
an
<a class="tref internalDFN" title="array" href="#dfn-array">
array
</a>.
</li>
<li>
If
<em>
element
</em>
has
an
<code>
@set
</code>
or
<code>
@list
</code>
property,
it
<em class="rfc2119" title="must">
must
</em>
be
the
only
property.
Set
<em>
element
</em>
to
the
value
of
<code>
@set
</code>
;
leave
<code>
@list
</code>
untouched.
</li>
<li>
If
<em>
element
</em>
has
just
a
<code>
@language
</code>
property,
set
<em>
element
</em>
to
<a class="tref internalDFN" title="null" href="#dfn-null">
null
</a>.
</li>
</ol>
</li>
<li>
Otherwise,
expand
<em>
element
</em>
according
to
the
<a href="#value-expansion">
Value
Expansion
</a>
rules,
passing
copies
of
the
<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
active
context
</a>
and
<a class="tref internalDFN" title="active_property" href="#dfn-active_property">
active
property
</a>.
</li>
</ol>
<p>
If,
after
the
algorithm
outlined
above
is
run,
the
resulting
<em>
element
</em>
is
an
<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
JSON
object
</a>
with
just
a
<code>
@graph
</code>
property,
<em>
element
</em>
is
set
to
the
value
of
<code>
@graph
</code>
's
value.
Finally,
if
<em>
element
</em>
is
a
<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
JSON
object
</a>,
it
is
wrapped
into
an
<a class="tref internalDFN" title="array" href="#dfn-array">
array
</a>.
</p>
</div>
</div>
<div id="compaction-1" class="section">
<h3>
<span class="secno">
4.8
</span>
Compaction
</h3>
<p>
Compaction
is
the
process
of
taking
a
JSON-LD
document
and
applying
a
context
such
that
the
most
compact
form
of
the
document
is
generated.
JSON
is
typically
expressed
in
a
very
compact,
key-value
format.
That
is,
full
IRIs
are
rarely
used
as
keys.
At
times,
a
JSON-LD
document
may
be
received
that
is
not
in
its
most
compact
form.
JSON-LD,
via
the
API,
provides
a
way
to
compact
a
JSON-LD
document.
</p>
<p>
For
example,
assume
the
following
JSON-LD
input
document:
</p>
<div class="example"><div class="example-title"><span>Example 15</span></div><pre class="example">{
  &quot;http://xmlns.com/foaf/0.1/name&quot;: &quot;Manu Sporny&quot;,
  &quot;http://xmlns.com/foaf/0.1/homepage&quot;: {
    &quot;@id&quot;: &quot;http://manu.sporny.org/&quot;
  }
}
</pre>
</div>
<p>
Additionally,
assume
the
following
developer-supplied
JSON-LD
context:
</p>
<div class="example"><div class="example-title"><span>Example 16</span></div><pre class="example">{
  &quot;@context&quot;: {
    &quot;name&quot;: &quot;http://xmlns.com/foaf/0.1/name&quot;,
    &quot;homepage&quot;: {
      &quot;@id&quot;: &quot;http://xmlns.com/foaf/0.1/homepage&quot;,
      &quot;@type&quot;: &quot;@id&quot;
    }
  }
}
</pre>
</div>
<p>
Running
the
JSON-LD
Compaction
algorithm
given
the
context
supplied
above
against
the
JSON-LD
input
document
provided
above
would
result
in
the
following
output:
</p>
<div class="example"><div class="example-title"><span>Example 17</span></div><pre class="example">{
  &quot;@context&quot;: {
    &quot;name&quot;: &quot;http://xmlns.com/foaf/0.1/name&quot;,
    &quot;homepage&quot;: {
      &quot;@id&quot;: &quot;http://xmlns.com/foaf/0.1/homepage&quot;,
      &quot;@type&quot;: &quot;@id&quot;
    }
  },
  &quot;name&quot;: &quot;Manu Sporny&quot;,
  &quot;homepage&quot;: &quot;http://manu.sporny.org/&quot;
}
</pre>
</div>
<p>
The
compaction
algorithm
also
enables
the
developer
to
map
any
expanded
format
into
an
application-specific
compacted
format.
While
the
context
provided
above
mapped
<code>
http://xmlns.com/foaf/0.1/name
</code>
to
<strong>
name
</strong>,
it
could
have
also
mapped
it
to
any
arbitrary
string
provided
by
the
developer.
</p>
<div id="compaction-algorithm" class="section">
<h4>
<span class="secno">
4.8.1
</span>
Compaction
Algorithm
</h4>
<p>
The
algorithm
takes
three
input
variables:
an
<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
active
context
</a>,
an
<a class="tref internalDFN" title="active_property" href="#dfn-active_property">
active
property
</a>,
and
an
<em>
element
</em>
to
be
compacted.
To
begin,
the
<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
active
context
</a>
is
set
to
the
result
of
performing
<a href="#context-processing">
Context
Processing
</a>
on
the
passed
<em>
context
</em>,
<a class="tref internalDFN" title="active_property" href="#dfn-active_property">
active
property
</a>
is
set
to
<a class="tref internalDFN" title="null" href="#dfn-null">
null
</a>,
and
<em>
element
</em>
is
set
to
the
result
of
performing
the
<a href="#expansion-algorithm">
Expansion
Algorithm
</a>
on
the
<a class="tref internalDFN" title="json-ld_input" href="#dfn-json-ld_input">
JSON-LD
input
</a>.
This
removes
any
existing
context
to
allow
the
given
<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
active
context
</a>
to
be
cleanly
applied.
</p>
<ol class="algorithm">
<li>
If
<em>
element
</em>
is
an
<a class="tref internalDFN" title="array" href="#dfn-array">
array
</a>,
process
each
entry
in
<em>
element
</em>
recursively
using
this
algorithm,
passing
a
copy
of
the
<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
active
context
</a>
and
the
<a class="tref internalDFN" title="active_property" href="#dfn-active_property">
active
property
</a>.
If
<em>
element
</em>
has
a
single
item,
the
compacted
value
is
that
item;
otherwise
the
compacted
value
is
<em>
element
</em>.
</li>
<li>
Otherwise,
if
<em>
element
</em>
is
an
object:
<ol class="algorithm">
<li>
If
<em>
element
</em>
has
an
<code>
@value
</code>
property
or
element
is
a
<a class="tref internalDFN" title="subject_reference" href="#dfn-subject_reference">
subject
reference
</a>,
return
the
result
of
performing
<a href="#value-compaction">
Value
Compaction
</a>
on
<em>
element
</em>
using
<a class="tref internalDFN" title="active_property" href="#dfn-active_property">
active
property
</a>.
</li>
<li>
Otherwise,
if
the
<a class="tref internalDFN" title="active_property" href="#dfn-active_property">
active
property
</a>
has
a
<code>
@container
</code>
mapping
to
<code>
@list
</code>
and
<em>
element
</em>
has
a
corresponding
<code>
@list
</code>
property,
recursively
compact
that
property's
value
passing
a
copy
of
the
<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
active
context
</a>
and
the
<a class="tref internalDFN" title="active_property" href="#dfn-active_property">
active
property
</a>
ensuring
that
the
result
is
an
array
and
removing
<a class="tref internalDFN" title="null" href="#dfn-null">
null
</a>
values.
Return
either
the
result
as
an
array,
as
an
object
with
a
key
of
<code>
@list
</code>
(or
appropriate
alias
from
<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
active
context
</a>
).
</li>
<li>
Otherwise,
construct
<em>
output
</em>
as
a
new
<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
JSON
object
</a>
used
for
returning
the
result
of
compacting
<em>
element
</em>.
For
each
<em>
property
</em>
and
<em>
value
</em>
in
<em>
element:
</em>
<ol class="algorithm">
<li>
If
<em>
property
</em>
is
<code>
@id
</code>
or
<code>
@type
</code>
<ol class="algorithm">
<li>
Set
<a class="tref internalDFN" title="active_property" href="#dfn-active_property">
active
property
</a>
to
the
result
of
performing
<a href="#iri-compaction">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
Compaction
</a>
on
<em>
property
</em>.
</li>
<li>
If
<em>
value
</em>
is
a
<a class="tref internalDFN" title="string" href="#dfn-string">
string
</a>,
the
compacted
<em>
value
</em>
is
the
result
of
performing
<a href="#iri-compaction">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
Compaction
</a>
on
<em>
value
</em>.
</li>
<li>
Otherwise,
<em>
value
</em>
<em class="rfc2119" title="must">
must
</em>
be
an
<a class="tref internalDFN" title="array" href="#dfn-array">
array
</a>.
Perform
<a href="#iri-compaction">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
Compaction
</a>
on
every
entry
of
<em>
value
</em>.
If
<em>
value
</em>
contains
just
one
entry,
<em>
value
</em>
is
set
to
that
entry.
</li>
<li>
Add
<a class="tref internalDFN" title="active_property" href="#dfn-active_property">
active
property
</a>
and
the
expanded
<em>
value
</em>
to
<em>
output
</em>.
</li>
</ol>
</li>
<li>
Otherwise,
<em>
value
</em>
<em class="rfc2119" title="must">
must
</em>
be
an
<a class="tref internalDFN" title="array" href="#dfn-array">
array
</a>.
</li>
<li>
If
<em>
value
</em>
is
empty:
<ol class="algorithm">
<li>
Set
<a class="tref internalDFN" title="active_property" href="#dfn-active_property">
active
property
</a>
to
the
result
of
performing
<a href="#iri-compaction">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
Compaction
</a>
on
<em>
property
</em>.
</li>
<li>
Create
an
entry
in
<em>
output
</em>
for
<a class="tref internalDFN" title="active_property" href="#dfn-active_property">
active
property
</a>
and
<em>
value
</em>.
</li>
</ol>
</li>
<li>
For
each
<em>
item
</em>
in
<em>
value
</em>:
<ol class="algorithm">
<li>
Set
<a class="tref internalDFN" title="active_property" href="#dfn-active_property">
active
property
</a>
to
the
result
of
performing
<a href="#iri-compaction">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
Compaction
</a>
for
<em>
property
</em>
and
<em>
item
</em>
using
the
<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
active
context
</a>.
</li>
<li>
Compact
<em>
item
</em>
by
recursively
performing
this
algorithm
passing
a
copy
of
the
<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
active
context
</a>
and
the
<a class="tref internalDFN" title="active_property" href="#dfn-active_property">
active
property
</a>.
</li>
<li>
If
an
entry
already
exists
in
<em>
output
</em>
for
<a class="tref internalDFN" title="active_property" href="#dfn-active_property">
active
property
</a>,
convert
it
to
an
<a class="tref internalDFN" title="array" href="#dfn-array">
array
</a>
if
necessary,
and
append
the
compacted
<em>
value
</em>.
</li>
<li>
Otherwise,
if
the
compacted
<em>
value
</em>
is
not
an
<a class="tref internalDFN" title="array" href="#dfn-array">
array
</a>
and
<a class="tref internalDFN" title="active_property" href="#dfn-active_property">
active
property
</a>
has
a
<code>
@container
</code>
mapping
to
<code>
@set
</code>,
create
an
entry
in
<em>
output
</em>
for
<a class="tref internalDFN" title="active_property" href="#dfn-active_property">
active
property
</a>
and
<em>
value
</em>
as
an
<a class="tref internalDFN" title="array" href="#dfn-array">
array
</a>.
</li>
<li>
Otherwise,
create
an
entry
in
<em>
output
</em>
for
<a class="tref internalDFN" title="active_property" href="#dfn-active_property">
active
property
</a>
and
<em>
value
</em>.
</li>
</ol>
</li>
</ol>
</li>
</ol>
</li>
<li>
Otherwise,
return
<em>
element
</em>
as
the
compacted
<em>
element
</em>.
<div class="issue">
<div class="issue-title">
<span>
Issue
7
</span>
</div>
<div class="">
Perhaps
this
should
also
call
<a href="#value-compaction">
Value
Compaction
</a>
on
native
types
and
strings,
which
could
consolidate
potential
transformation
in
one
place.
</div>
</div>
</li>
</ol>
<p>
If,
after
the
algorithm
outlined
above
is
run,
the
resulting
<em>
element
</em>
is
an
<a class="tref internalDFN" title="array" href="#dfn-array">
array
</a>,
put
<em>
element
</em>
into
the
<code>
@graph
</code>
property
of
a
new
<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
JSON
object
</a>
and
then
set
<em>
element
</em>
to
that
<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
JSON
object
</a>.
Finally,
add
a
<code>
@context
</code>
property
to
<em>
element
</em>
and
set
it
to
the
initially
passed
<em>
context
</em>.
</p>
</div>
</div>
<div id="rdf-conversion" class="section">
<h3>
<span class="secno">
4.9
</span>
RDF
Conversion
</h3>
<p>
A
JSON-LD
document
<em class="rfc2119" title="may">
may
</em>
be
converted
between
other
RDF-compatible
document
formats
using
the
algorithms
specified
in
this
section.
</p>
<p>
The
JSON-LD
Processing
Model
describes
processing
rules
for
extracting
RDF
from
a
JSON-LD
document,
and
for
transforming
an
array
of
<a href="#idl-def-Quad" class="idlType">
<code>
Quad
</code>
</a>
retrieved
by
processing
another
serialization
format
into
JSON-LD.
Note
that
many
uses
of
JSON-LD
may
not
require
generation
of
RDF.
</p>
<p>
The
processing
algorithms
described
in
this
section
are
provided
in
order
to
demonstrate
how
one
might
implement
a
JSON-LD
to
RDF
processor.
Conformant
implementations
are
only
required
to
produce
the
same
type
and
number
of
quads
during
the
output
process
and
are
not
required
to
implement
the
algorithm
exactly
as
described.
</p>
<div class="informative section" id="overview">
<h4>
<span class="secno">
4.9.1
</span>
Overview
</h4>
<p>
<em>
This
section
is
non-normative.
</em>
</p>
<p>
JSON-LD
is
intended
to
have
an
easy
to
parse
grammar
that
closely
models
existing
practice
in
using
JSON
for
describing
object
representations.
This
allows
the
use
of
existing
libraries
for
parsing
JSON.
</p>
<p>
As
with
other
grammars
used
for
describing
<a class="tref internalDFN" title="linked_data" href="#dfn-linked_data">
Linked
Data
</a>,
a
key
concept
is
that
of
a
<a class="tref internalDFN" title="node" href="#dfn-node">
node
</a>
in
a
<a class="tref internalDFN" title="linked_data_graph" href="#dfn-linked_data_graph">
linked
data
graph
</a>.
Nodes
may
be
of
three
basic
types.
The
first
is
the
<a class="datatype idlType" title="IRI" href="#idl-def-IRI">
<code>
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</code>
</a>,
which
is
used
to
refer
to
<a class="tref internalDFN" title="node" href="#dfn-node">
node
</a>
s
in
other
<a class="tref internalDFN" title="linked_data_graph" href="#dfn-linked_data_graph">
linked
data
graph
</a>
s.
The
second
is
the
<a class="tref internalDFN" title="blank_node" href="#dfn-blank_node">
blank
node
</a>,
which
are
nodes
for
which
an
external
name
does
not
exist,
or
is
not
known.
The
third
is
a
<a class="tref internalDFN" title="literal" href="#dfn-literal">
Literal
</a>,
which
express
values
such
as
strings,
dates
and
other
information
having
a
lexical
form,
possibly
including
an
explicit
language
or
datatype.
</p>
<p>
Data
described
with
JSON-LD
may
be
considered
to
be
a
graph
made
up
of
<a class="tref internalDFN" title="subject" href="#dfn-subject">
subject
</a>
and
<a class="tref internalDFN" title="object" href="#dfn-object">
object
</a>
<a class="tref internalDFN" title="node" href="#dfn-node">
nodes
</a>
related
via
a
<a class="tref internalDFN" title="property" href="#dfn-property">
property
</a>
<a class="tref internalDFN" title="node" href="#dfn-node">
node
</a>.
Specific
implementations
may
also
choose
to
operate
on
the
document
as
a
normal
JSON
description
of
objects
having
attributes.
Both
approaches
are
valid
ways
to
interact
with
JSON-LD
documents.
</p>
</div>
<div class="informative section" id="parsing-examples">
<h4>
<span class="secno">
4.9.2
</span>
Parsing
Examples
</h4>
<p>
<em>
This
section
is
non-normative.
</em>
</p>
<p>
The
following
examples
show
simple
transformations
of
JSON-LD
documents
to
Turtle
[
<cite>
<a class="bibref" rel="biblioentry" href="#bib-TURTLE-TR">
TURTLE-TR
</a>
</cite>
].
</p>
<p>
The
first
example
uses
a
simple
document
containing
a
simple
FOAF
profile:
</p>
<div class="example"><div class="example-title"><span>Example 18</span></div><pre class="example">{
  &quot;@context&quot;: {&quot;foaf&quot;: &quot;http://xmlns.com/foaf/0.1/&quot;},
  &quot;@id&quot;: &quot;http://greggkellogg.net/foaf#me&quot;,
  &quot;@type&quot;: &quot;foaf:Person&quot;,
  &quot;foaf:name&quot;: &quot;Gregg Kellogg&quot;,
  &quot;foaf:knows&quot;: {
    &quot;@type&quot;: &quot;foaf:Person&quot;,
    &quot;foaf:name&quot;: &quot;Manu Sporny&quot;
  }
}
</pre>
</div>
<p>
This
translates
fairly
directly
to
a
similar
Turtle
document:
</p>
<div class="example"><div class="example-title"><span>Example 19</span></div><pre class="example">@prefix foaf: &lt;http://xmlns.com/foaf/0.1/&gt;.
&lt;http://greggkellogg.net/foaf#me&gt; a foaf:Person;
  foaf:name &quot;Gregg Kellogg&quot;;
foaf:knows
[
a
foaf:Person;
foaf:name
&quot;Manu
Sporny&quot;].
</pre>
</div>
<p>
The
actual
parsing
steps
first
require
that
the
JSON-LD
document
be
expanded,
to
eliminate
the
<code>
@context
</code>:
</p>
<div class="example"><div class="example-title"><span>Example 20</span></div><pre class="example">[{
  &quot;@id&quot;: &quot;http://greggkellogg.net/foaf#me&quot;,
  &quot;@type&quot;: [&quot;http://xmlns.com/foaf/0.1/Person&quot;],
  &quot;http://xmlns.com/foaf/0.1/name&quot;: [{&quot;@value&quot;: &quot;Gregg Kellogg&quot;}],
  &quot;http://xmlns.com/foaf/0.1/knows&quot;: [{
    &quot;@type&quot;: [&quot;http://xmlns.com/foaf/0.1/Person&quot;],
    &quot;http://xmlns.com/foaf/0.1/name&quot;: [{&quot;@value&quot;: &quot;Manu Sporny&quot;}]
  }]
}]
</pre>
</div>
<p>
The
process
of
translating
this
to
RDF
then
operates
over
each
<a class="tref internalDFN" title="subject_definition" href="#dfn-subject_definition">
subject
definition
</a>
to
find
a
subject,
each
<a class="tref internalDFN" title="property" href="#dfn-property">
property
</a>
to
find
an
RDF
<em>
predicate
</em>,
and
each
value
of
that
property
to
find
an
<a class="tref internalDFN" title="object" href="#dfn-object">
object
</a>.
In
this
case,
each
property
has
just
a
single
object:
<code>
foaf:name
</code>
identifies
a
<a class="tref internalDFN" title="literal" href="#dfn-literal">
literal
</a>,
and
<code>
foaf:knows
</code>
identifies
a
second
<a class="tref internalDFN" title="subject_definition" href="#dfn-subject_definition">
subject
definition
</a>
similar
to
Turtle's
<code>
blankNodePropertyList
</code>.
</p>
<p>
After
expansion,
JSON-LD
<a class="tref internalDFN" title="number" href="#dfn-number">
numbers
</a>,
<a class="tref internalDFN" title="true" href="#dfn-true">
booleans
</a>,
typed-
and
language-tagged-
<a class="tref internalDFN" title="literal" href="#dfn-literal">
literals
</a>,
and
<a class="tref internalDFN" title="iri" href="#dfn-iri">
IRIs
</a>
become
explicit,
and
can
be
directly
transformed
into
their
RDF
representations.
</p>
<div class="example"><div class="example-title"><span>Example 21</span></div><pre class="example">[{
  &quot;@id&quot;: &quot;http://greggkellogg.net/foaf#me&quot;,
  &quot;@type&quot;: [&quot;http://xmlns.com/foaf/0.1/Person&quot;],
  &quot;http://xmlns.com/foaf/0.1/name&quot;: [{&quot;@value&quot;: &quot;Gregg Kellogg&quot;}],
  <span class="diff">&quot;http://xmlns.com/foaf/0.1/currentProject&quot;: [{&quot;@id&quot;: &quot;http://json-ld.org/&quot;}],
  &quot;http://xmlns.com/foaf/0.1/birthday&quot;: [{
    &quot;@value&quot;: &quot;1957-02-27&quot;,
    &quot;@type&quot;: &quot;http://www.w3.org/2001/XMLSchema#date&quot;
  }],</span>
  &quot;http://xmlns.com/foaf/0.1/knows&quot;: [{
    &quot;@type&quot;: [&quot;http://xmlns.com/foaf/0.1/Person&quot;],
    &quot;http://xmlns.com/foaf/0.1/name&quot;: [{&quot;@value&quot;: &quot;Manu Sporny&quot;}]
  }]
}]
</pre>
</div>
<p>
Translates
to:
</p>
<div class="example"><div class="example-title"><span>Example 22</span></div><pre class="example">@prefix foaf: &lt;http://xmlns.com/foaf/0.1/&gt;.
@prefix xsd: &lt;http://www.w3.org/2001/XMLSchema#&gt;.
&lt;http://greggkellogg.net/foaf#me&gt; a foaf:Person;
  foaf:name &quot;Gregg Kellogg&quot;;
  <span class="diff">foaf:currentProject &lt;http://json-ld.org/&gt;;
  foaf:birthday &quot;1957-02-27&quot;^^xsd:date;</span>
foaf:knows
[
a
foaf:Person;
foaf:name
&quot;Manu
Sporny&quot;].
</pre>
</div>
</div>
<div id="convert-to-rdf-algorithm" class="section">
<h4>
<span class="secno">
4.9.3
</span>
Convert
to
RDF
Algorithm
</h4>
<p>
The
algorithm
below
is
designed
for
in-memory
implementations
with
random
access
to
<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
JSON
object
</a>
elements.
</p>
<p>
A
conforming
JSON-LD
processor
implementing
RDF
conversion
<em class="rfc2119" title="must">
must
</em>
implement
a
processing
algorithm
that
results
in
the
same
set
of
RDF
<a class="tref internalDFN" title="quad" href="#dfn-quad">
Quads
</a>
that
the
following
algorithm
generates:
</p>
<p>
The
algorithm
takes
five
input
variables:
a
<em>
element
</em>
to
be
converted,
an
<a class="tref internalDFN" title="active_subject" href="#dfn-active_subject">
active
subject
</a>,
<a class="tref internalDFN" title="active_property" href="#dfn-active_property">
active
property
</a>
and
<a class="tref internalDFN" title="graph_name" href="#dfn-graph_name">
graph
name
</a>.
To
begin,
the
<a class="tref internalDFN" title="active_subject" href="#dfn-active_subject">
active
subject
</a>,
<a class="tref internalDFN" title="active_property" href="#dfn-active_property">
active
property
</a>
and
<a class="tref internalDFN" title="graph_name" href="#dfn-graph_name">
graph
name
</a>
are
set
to
<a class="tref internalDFN" title="null" href="#dfn-null">
null
</a>,
and
<em>
element
</em>
is
set
to
the
result
of
performing
the
<a href="#expansion-algorithm">
Expansion
Algorithm
</a>
on
the
<a class="tref internalDFN" title="json-ld_input" href="#dfn-json-ld_input">
JSON-LD
input
</a>.
This
removes
any
existing
context
to
allow
the
given
context
to
be
cleanly
applied.
</p>
<ol class="algorithm">
<li id="processing-step-associative">
If
<em>
element
</em>
is
a
<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
JSON
object
</a>,
perform
the
following
steps:
<ol class="algorithm">
<li>
Set
<a class="tref internalDFN" title="active_object" href="#dfn-active_object">
active
object
</a>
to
<a class="tref internalDFN" title="null" href="#dfn-null">
null
</a>.
</li>
<li>
If
<em>
element
</em>
has
a
<code>
@value
</code>
property:
<ol class="algorithm">
<li>
If
the
value
of
<code>
@value
</code>
is
a
<a class="tref internalDFN" title="number" href="#dfn-number">
number
</a>,
set
the
<a class="tref internalDFN" title="active_object" href="#dfn-active_object">
active
object
</a>
to
a
<a class="tref internalDFN" title="typed_literal" href="#dfn-typed_literal">
typed
literal
</a>
using
a
string
representation
of
the
value
as
defined
in
the
section
<a href="#data-round-tripping">
Data
Round
Tripping
</a>.
Set
datatype
to
the
value
of
the
<code>
@type
</code>
property
if
it
exists,
otherwise
either
<code>
xsd:integer
</code>
or
<code>
xsd:double
</code>,
depending
on
if
the
value
contains
a
fractional
and/or
an
exponential
component.
</li>
<li>
Otherwise,
if
the
value
of
<code>
@value
</code>
is
<strong>
true
</strong>
or
<strong>
false
</strong>,
set
the
<a class="tref internalDFN" title="active_object" href="#dfn-active_object">
active
object
</a>
to
a
<a class="tref internalDFN" title="typed_literal" href="#dfn-typed_literal">
typed
literal
</a>
created
from
the
string
representation
of
the
value.
Set
datatype
to
the
value
of
the
<code>
@type
</code>
property
if
it
exists,
otherwise
<code>
xsd:boolean
</code>.
</li>
<li>
Otherwise,
if
<em>
element
</em>
contains
a
<code>
@type
</code>
property,
set
the
<a class="tref internalDFN" title="active_object" href="#dfn-active_object">
active
object
</a>
to
a
<a class="tref internalDFN" title="typed_literal" href="#dfn-typed_literal">
typed
literal
</a>.
</li>
<li>
Otherwise,
if
<em>
element
</em>
contains
a
<code>
@language
</code>
property,
set
the
<a class="tref internalDFN" title="active_object" href="#dfn-active_object">
active
object
</a>
to
a
<a class="tref internalDFN" title="language-tagged_literal" href="#dfn-language-tagged_literal">
language-tagged
literal
</a>.
</li>
<li>
Otherwise,
set
the
<a class="tref internalDFN" title="active_object" href="#dfn-active_object">
active
object
</a>
to
a
<a class="tref internalDFN" title="typed_literal" href="#dfn-typed_literal">
typed
literal
</a>
using
<code>
xsd:string
</code>
as
the
datatype.
</li>
</ol>
</li>
<li>
If
<em>
element
</em>
has
a
<code>
@list
</code>
property
the
value
<em class="rfc2119" title="must">
must
</em>
be
an
<a class="tref internalDFN" title="array" href="#dfn-array">
array
</a>.
Process
its
value
as
a
list
as
described
in
<a href="#list-conversion">
List
Conversion
</a>
using
the
return
value
as
the
<a class="tref internalDFN" title="active_object" href="#dfn-active_object">
active
object
</a>
</li>
<li>
If
<a class="tref internalDFN" title="active_object" href="#dfn-active_object">
active
object
</a>
is
not
<a class="tref internalDFN" title="null" href="#dfn-null">
null
</a>:
<ol class="algorithm">
<li>
If
neither
<a class="tref internalDFN" title="active_subject" href="#dfn-active_subject">
active
subject
</a>
nor
<a class="tref internalDFN" title="active_property" href="#dfn-active_property">
active
property
</a>
are
<a class="tref internalDFN" title="null" href="#dfn-null">
null
</a>,
generate
a
<a href="#idl-def-Quad" class="idlType">
<code>
Quad
</code>
</a>
representing
<a class="tref internalDFN" title="active_subject" href="#dfn-active_subject">
active
subject
</a>,
<a class="tref internalDFN" title="active_property" href="#dfn-active_property">
active
property
</a>,
<a class="tref internalDFN" title="active_object" href="#dfn-active_object">
active
object
</a>,
and
<a class="tref internalDFN" title="graph_name" href="#dfn-graph_name">
graph
name
</a>.
</li>
<li>
Return
<a class="tref internalDFN" title="active_object" href="#dfn-active_object">
active
object
</a>.
</li>
</ol>
</li>
<li id="processing-step-subject">
If
<em>
element
</em>
has
a
<code>
@id
</code>
property,
the
value
<em class="rfc2119" title="must">
must
</em>
be
a
<a class="tref internalDFN" title="string" href="#dfn-string">
string
</a>,
set
the
<a class="tref internalDFN" title="active_subject" href="#dfn-active_subject">
active
subject
</a>
to
the
previously
expanded
value
(either
a
<a class="tref internalDFN" title="blank_node" href="#dfn-blank_node">
blank
node
</a>
or
an
<a class="datatype idlType" title="IRI" href="#idl-def-IRI">
<code>
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</code>
</a>
).
</li>
<li>
Otherwise,
if
<em>
element
</em>
does
not
have
a
<code>
@id
</code>
property,
set
the
<a class="tref internalDFN" title="active_subject" href="#dfn-active_subject">
active
subject
</a>
to
newly
generated
<a class="tref internalDFN" title="blank_node" href="#dfn-blank_node">
blank
node
</a>.
</li>
<li>
Process
each
<em>
property
</em>
and
<em>
value
</em>
in
<em>
element
</em>,
ordered
by
<em>
property
</em>,
as
follows:
<ol class="algorithm">
<li>
If
<em>
property
</em>
is
<code>
@type
</code>,
set
the
<a class="tref internalDFN" title="active_property" href="#dfn-active_property">
active
property
</a>
to
<code>
rdf:type
</code>.
</li>
<li>
Otherwise,
if
<em>
property
</em>
is
<code>
@graph
</code>,
process
<em>
value
</em>
algorithm
recursively,
using
<a class="tref internalDFN" title="active_subject" href="#dfn-active_subject">
active
subject
</a>
as
<a class="tref internalDFN" title="graph_name" href="#dfn-graph_name">
graph
name
</a>
and
null
values
for
<a class="tref internalDFN" title="active_subject" href="#dfn-active_subject">
active
subject
</a>
and
<a class="tref internalDFN" title="active_property" href="#dfn-active_property">
active
property
</a>
and
then
proceed
to
next
property.
</li>
<li>
Otherwise,
if
<em>
property
</em>
is
a
<a class="tref internalDFN" title="keyword" href="#dfn-keyword">
keyword
</a>,
skip
this
step.
</li>
<li>
Otherwise,
set
<a class="tref internalDFN" title="active_property" href="#dfn-active_property">
active
property
</a>
to
the
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
value
of
<em>
property
</em>.
</li>
<li>
Process
<em>
value
</em>
recursively
using
this
algorithm,
passing
copies
of
<a class="tref internalDFN" title="active_subject" href="#dfn-active_subject">
active
subject
</a>,
<a class="tref internalDFN" title="active_property" href="#dfn-active_property">
active
property
</a>
and
<a class="tref internalDFN" title="graph_name" href="#dfn-graph_name">
graph
name
</a>.
</li>
</ol>
</li>
<li>
Set
<a class="tref internalDFN" title="active_object" href="#dfn-active_object">
active
object
</a>
to
<a class="tref internalDFN" title="active_subject" href="#dfn-active_subject">
active
subject
</a>.
</li>
</ol>
</li>
<li>
Otherwise,
if
<em>
element
</em>
is
an
<a class="tref internalDFN" title="array" href="#dfn-array">
array
</a>,
process
each
value
in
the
<a class="tref internalDFN" title="array" href="#dfn-array">
array
</a>
as
follows,
process
<em>
element
</em>
recursively
using
this
algorithm,
using
copies
of
<a class="tref internalDFN" title="active_subject" href="#dfn-active_subject">
active
subject
</a>,
<a class="tref internalDFN" title="active_property" href="#dfn-active_property">
active
property
</a>,
and
<a class="tref internalDFN" title="graph_name" href="#dfn-graph_name">
graph
name
</a>.
</li>
<li>
Otherwise,
if
<em>
element
</em>
is
a
<a class="tref internalDFN" title="string" href="#dfn-string">
string
</a>,
then
the
<a class="tref internalDFN" title="active_property" href="#dfn-active_property">
active
property
</a>
must
be
<code>
rdf:type
</code>
so
set
the
<a class="tref internalDFN" title="active_object" href="#dfn-active_object">
active
object
</a>
to
an
<a class="datatype idlType" title="IRI" href="#idl-def-IRI">
<code>
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</code>
</a>.
</li>
<li>
If
any
of
these
steps
created
an
<a class="tref internalDFN" title="active_object" href="#dfn-active_object">
active
object
</a>
and
neither
<a class="tref internalDFN" title="active_subject" href="#dfn-active_subject">
active
subject
</a>
nor
<a class="tref internalDFN" title="active_property" href="#dfn-active_property">
active
property
</a>
are
<a class="tref internalDFN" title="null" href="#dfn-null">
null
</a>,
generate
a
<a href="#idl-def-Quad" class="idlType">
<code>
Quad
</code>
</a>
using
<a class="tref internalDFN" title="active_subject" href="#dfn-active_subject">
active
subject
</a>,
<a class="tref internalDFN" title="active_property" href="#dfn-active_property">
active
property
</a>,
<a class="tref internalDFN" title="active_object" href="#dfn-active_object">
active
object
</a>
and
<a class="tref internalDFN" title="graph_name" href="#dfn-graph_name">
graph
name
</a>.
</li>
<li>
Return
<a class="tref internalDFN" title="active_object" href="#dfn-active_object">
active
object
</a>.
</li>
</ol>
</div>
<div id="list-conversion" class="section">
<h4>
<span class="secno">
4.9.4
</span>
List
Conversion
</h4>
<p>
List
Conversion
is
the
process
of
taking
an
<a class="tref internalDFN" title="array" href="#dfn-array">
array
</a>
of
values
and
adding
them
to
a
newly
created
<cite>
<a href="http://www.w3.org/TR/rdf-schema/#ch_collectionvocab">
RDF
Collection
</a>
</cite>
(see
[
<cite>
<a class="bibref" rel="biblioentry" href="#bib-RDF-SCHEMA">
RDF-SCHEMA
</a>
</cite>
])
by
linking
each
element
of
the
list
using
<code>
rdf:first
</code>
and
<code>
rdf:next
</code>,
terminating
the
list
with
<code>
rdf:nil
</code>
using
the
following
sequence:
</p>
<p>
The
algorithm
is
invoked
with
an
<a class="tref internalDFN" title="array" href="#dfn-array">
array
</a>
<em>
array
</em>,
the
<a class="tref internalDFN" title="active_property" href="#dfn-active_property">
active
property
</a>
and
returns
a
value
to
be
used
as
an
<a class="tref internalDFN" title="active_object" href="#dfn-active_object">
active
object
</a>
in
the
calling
location.
</p>
<div class="note">
<div class="note-title">
<span>
Note
</span>
</div>
<div class="">
This
algorithm
does
not
support
lists
containing
lists.
</div>
</div>
<ol class="algorithm">
<li>
If
<em>
array
</em>
is
empty
return
<code>
rdf:nil
</code>.
</li>
<li>
Otherwise,
generate
a
<a href="#idl-def-Quad" class="idlType">
<code>
Quad
</code>
</a>
using
using
the
<a class="tref internalDFN" title="active_subject" href="#dfn-active_subject">
active
subject
</a>,
<a class="tref internalDFN" title="active_property" href="#dfn-active_property">
active
property
</a>
and
a
newly
generated
<a class="tref internalDFN" title="blank_node" href="#dfn-blank_node">
blank
node
</a>
identified
as
<em>
first
<a class="tref internalDFN" title="blank_node" href="#dfn-blank_node">
blank
node
</a>
</em>.
</li>
<li>
For
each
element
in
<em>
array
</em>
other
than
the
last
element:
<ol class="algorithm">
<li>
Create
a
processor
state
using
<em>
first
blank
node
</em>
as
the
<a class="tref internalDFN" title="active_subject" href="#dfn-active_subject">
active
subject
</a>,
and
<code>
rdf:first
</code>
as
the
<a class="tref internalDFN" title="active_property" href="#dfn-active_property">
active
property
</a>.
<ol class="algorithm">
<li>
Process
the
value
starting
at
<a href="#processing-step-associative">
Step
1
</a>.
</li>
<li>
Proceed
using
the
previous
<a class="tref internalDFN" title="processor_state" href="#dfn-processor_state">
processor
state
</a>.
</li>
</ol>
</li>
<li>
Unless
this
is
the
last
element
in
<em>
array
</em>,
generate
a
new
<a class="tref internalDFN" title="blank_node" href="#dfn-blank_node">
blank
node
</a>
identified
as
<em>
rest
blank
node
</em>,
otherwise
use
<code>
rdf:nil
</code>.
</li>
<li>
Generate
a
new
<a href="#idl-def-Quad" class="idlType">
<code>
Quad
</code>
</a>
using
<em>
first
blank
node
</em>,
<code>
rdf:rest
</code>
and
<em>
rest
blank
node
</em>.
</li>
<li>
Set
<em>
first
blank
node
</em>
to
<em>
rest
blank
node
</em>.
</li>
<li>
Return
<em>
first
blank
node
</em>.
</li>
</ol>
</li>
</ol>
</div>
<div id="convert-from-rdf-algorithm" class="section">
<h4>
<span class="secno">
4.9.5
</span>
Convert
from
RDF
Algorithm
</h4>
<p>
In
some
cases,
data
exists
natively
in
Triples
or
Quads
form;
for
example,
if
the
data
was
originally
represented
in
an
RDF
graph
or
triple/quad
store.
This
algorithm
is
designed
to
simply
translate
an
array
of
<a class="datatype idlType" title="quad" href="#idl-def-quad">
<code>
Quads
</code>
</a>
into
a
JSON-LD
document.
</p>
<p>
When
expanding
<a class="tref internalDFN" title="typed_literal" href="#dfn-typed_literal">
typed
literal
</a>
values
having
a
datatype
of
<code>
xsd:string
</code>,
the
<code>
@type
</code>
<em class="rfc2119" title="must not">
must
not
</em>
be
set
to
<code>
xsd:string
</code>
and
the
resulting
value
<em class="rfc2119" title="must">
must
</em>
have
only
a
<code>
@value
</code>
property.
</p>
<p>
The
conversion
algorithm
takes
a
single
parameter
<em>
input
</em>
in
the
form
of
an
array
of
<a href="#idl-def-Quad" class="idlType">
<code>
Quad
</code>
</a>
representations.
</p>
<ol class="algorithm">
<li id="new_graph">
Construct
<em>
defaultGraph
</em>
as
a
<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
JSON
object
</a>
containing
<em>
subjects
</em>
and
<em>
listMap
</em>,
each
an
empty
<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
JSON
object
</a>.
</li>
<li>
Construct
<em>
graphs
</em>
as
a
<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
JSON
object
</a>
containing
<em>
defaultGraph
</em>
identified
by
an
empty
<a class="tref internalDFN" title="string" href="#dfn-string">
string
</a>.
</li>
<li>
For
each
quad
in
<em>
input
</em>:
<ol class="algorithm">
<li>
Set
<em>
graph
</em>
to
the
entry
in
<em>
graphs
</em>
identified
by
<em>
name
</em>,
initializing
it
to
a
new
entry
using
the
mechanism
described
in
<a href="#new_graph">
Step
1
</a>.
</li>
<li>
If
<em>
property
</em>
is
<code>
rdf:first
</code>,
use
the
entry
in
<em>
graph.listMap
</em>
indexed
by
<em>
subject
</em>,
initializing
it
to
a
new
<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
JSON
object
</a>
if
nesessary.
Represent
<em>
object
</em>
in
expanded
form,
as
described
in
<a href="#value-expansion">
Value
Expansion
</a>.
Add
the
resulting
<em>
object
representation
</em>
to
the
entry
indexed
by
<em>
first
</em>,
and
skip
to
the
next
quad.
</li>
<li>
If
<em>
property
</em>
is
<code>
rdf:rest
</code>:
<ol class="algorithm">
<li>
If
<em>
object
</em>
is
a
<a class="tref internalDFN" title="blank_node" href="#dfn-blank_node">
blank
node
</a>,
use
the
entry
in
<em>
graph.listMap
</em>
indexed
by
<em>
subject
</em>,
initializing
it
to
a
new
<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
JSON
object
</a>
if
necessary.
Add
the
<em>
nominalValue
</em>
of
<em>
object
</em>
to
the
entry
indexed
by
<em>
rest
</em>.
</li>
<li>
Skip
to
the
next
quad.
</li>
</ol>
</li>
<li>
If
<em>
name
</em>
is
not
<a class="tref internalDFN" title="null" href="#dfn-null">
null
</a>,
and
<em>
defaultGraph.subjects
</em>
does
not
contain
an
entry
for
<em>
name
</em>,
create
a
new
entry
for
<em>
name
</em>
from
a
new
<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
JSON
object
</a>
with
key/value
pair
of
<code>
@id
</code>
and
a
string
representation
of
<em>
name
</em>.
</li>
<li>
Set
<em>
value
</em>
as
the
entry
from
<em>
graph.subjects
</em>
for
<em>
subject
</em>,
initializing
it
to
a
new
<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
JSON
object
</a>
with
key/value
pair
of
<code>
@id
</code>
and
a
string
representation
of
<em>
subject
</em>
if
necessary.
</li>
<li>
If
<em>
property
</em>
is
<code>
rdf:type
</code>
and
the
<em>
notType
</em>
option
is
present
and
not
<a class="tref internalDFN" title="true" href="#dfn-true">
true
</a>:
<ol class="algorithm">
<li>
Append
the
string
representation
of
<em>
object
</em>
to
the
array
value
for
the
key
<code>
@type
</code>,
creating
an
entry
in
<em>
value
</em>
if
necessary.
</li>
</ol>
</li>
<li>
Otherwise,
if
<em>
object
</em>
is
<code>
rdf:nil
</code>:
<ol class="algorithm">
<li>
Let
<em>
key
</em>
be
the
string
representation
of
<em>
property
</em>.
</li>
<li>
Append
an
empty
<code>
@list
</code>
representation
to
the
array
value
for
<em>
key
</em>,
creating
an
entry
in
<em>
value
</em>
if
necessary.
</li>
</ol>
</li>
<li>
Otherwise,
<ol class="algorithm">
<li>
Let
<em>
key
</em>
be
the
string
representation
of
<em>
property
</em>
and
let
<em>
object
representation
</em>
be
<em>
object
</em>
represented
in
expanded
form
as
described
in
<a href="#value-expansion">
Value
Expansion
</a>.
</li>
<li>
If
<em>
object
</em>
is
a
<a class="tref internalDFN" title="blank_node" href="#dfn-blank_node">
blank
node
</a>,
use
the
entry
in
<em>
graph.listMap
</em>
indexed
by
<em>
object
</em>,
initializing
it
to
a
new
<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
JSON
object
</a>
if
nesessary.
Add
an
entry
for
<em>
head
</em>
with
<em>
object
representation
</em>.
</li>
<li>
Append
<em>
object
representation
</em>
to
the
array
value
for
<em>
key
</em>,
creating
an
entry
in
<em>
value
</em>
if
necessary.
</li>
</ol>
</li>
</ol>
</li>
<li>
For
each
<em>
name
</em>
and
<em>
graph
</em>
in
<em>
graphs
</em>:
<ol class="algorithm">
<li>
For
each
<em>
subject
</em>
and
<em>
entry
</em>
in
<em>
graph
</em>
where
<em>
entry
</em>
has
both
<em>
head
</em>
and
<em>
first
</em>
keys:
<ol class="algorithm">
<li>
Set
<em>
value
</em>
to
the
value
of
<em>
head
</em>
in
<em>
entry
</em>.
</li>
<li>
Remove
the
entry
for
<code>
@id
</code>
in
<em>
value
</em>.
</li>
<li>
Add
an
entry
to
<em>
value
</em>
for
<code>
@list
</code>
initialized
to
a
new
array
containing
the
value
of
<em>
first
</em>
from
<em>
entry
</em>.
</li>
<li>
While
<em>
entry
</em>
has
a
key
for
<em>
rest
</em>:
<ol class="algorithm">
<li>
Set
<em>
entry
</em>
to
the
value
of
<em>
graph.listMap
</em>
for
<em>
entry.rest
</em>.
</li>
<li>
Add
the
value
for
<em>
entry.first
</em>
to
the
list
array.
</li>
</ol>
</li>
</ol>
</li>
</ol>
</li>
<li>
Create
<em>
array
</em>
as
an
empty
<a class="tref internalDFN" title="array" href="#dfn-array">
array
</a>.
</li>
<li>
For
each
<em>
subject
</em>
and
<em>
entry
</em>
in
<em>
defaultGraph.subjects
</em>
ordered
by
<em>
subject
</em>:
<ol class="algorithm">
<li>
Add
<em>
entry
</em>
to
<em>
array
</em>.
</li>
<li>
If
<em>
graphs
</em>
has
an
entry
for
<em>
subject
</em>,
add
a
property
<code>
@graph
</code>
in
<em>
entry
</em>
containing
the
ordered
entries
from
<em>
graphs[subject].subjects
</em>.
</li>
</ol>
</li>
<li>
Return
<em>
array
</em>
as
the
result.
</li>
</ol>
</div>
</div>
</div>
<div id="data-round-tripping" class="section">
<h2>
<span class="secno">
5.
</span>
Data
Round
Tripping
</h2>
<p>
When
coercing
numbers
to
<strong>
xsd:integer
</strong>
or
<strong>
xsd:double
</strong>
as
it,
e.g.,
happens
during
<a href="#rdf-conversion">
RDF
Conversion
</a>,
implementers
<em class="rfc2119" title="must">
must
</em>
ensure
that
the
result
is
a
canonical
lexical
form
in
the
form
of
a
<a class="tref internalDFN" title="string" href="#dfn-string">
string
</a>.
A
<dfn title="canonical_lexical_form" id="dfn-canonical_lexical_form">
canonical
lexical
form
</dfn>
is
a
set
of
literals
from
among
the
valid
set
of
literals
for
a
datatype
such
that
there
is
a
one-to-one
mapping
between
the
canonical
lexical
form
and
a
value
in
the
value
space
as
defined
in
[
<cite>
<a class="bibref" rel="biblioentry" href="#bib-XMLSCHEMA11-2">
XMLSCHEMA11-2
</a>
</cite>
]].
In
other
words,
every
value
<em class="rfc2119" title="must">
must
</em>
be
converted
to
a
deterministic
string
representation.
</p>
<p>
The
canonical
lexical
form
of
an
<em>
integer
</em>,
i.e.,
a
number
without
fractions
or
a
number
coerced
to
<strong>
xsd:integer
</strong>,
is
a
finite-length
sequence
of
decimal
digits
(
<code>
0-9
</code>
)
with
an
optional
leading
minus
sign;
leading
zeroes
are
prohibited.
To
convert
the
number
in
JavaScript,
implementers
can
use
the
following
snippet
of
code:
</p>
<div class="example">
<div class="example-title">
<span>
Example
23
</span>
</div>
<pre class="example">
(value).toFixed(0).toString()
</pre>
</div>
<p>
The
canonical
lexical
form
of
a
<em>
double
</em>,
i.e.,
a
number
with
fractions
or
a
number
coerced
to
<strong>
xsd:double
</strong>,
consists
of
a
mantissa
followed
by
the
character
&quot;E&quot;,
followed
by
an
exponent.
The
mantissa
<em class="rfc2119" title="must">
must
</em>
be
a
decimal
number.
The
exponent
<em class="rfc2119" title="must">
must
</em>
be
an
integer.
Leading
zeroes
and
a
preceding
plus
sign
(
<code>
+
</code>
)
are
prohibited
in
the
exponent.
If
the
exponent
is
zero,
it
must
be
indicated
by
<code>
E0
</code>.
For
the
mantissa,
the
preceding
optional
plus
sign
is
prohibited
and
the
decimal
point
is
required.
Leading
and
trailing
zeroes
are
prohibited
subject
to
the
following:
number
representations
must
be
normalized
such
that
there
is
a
single
digit
which
is
non-zero
to
the
left
of
the
decimal
point
and
at
least
a
single
digit
to
the
right
of
the
decimal
point
unless
the
value
being
represented
is
zero.
The
canonical
representation
for
zero
is
<code>
0.0E0
</code>.
To
convert
the
number
in
JavaScript,
implementers
can
use
the
following
snippet
of
code:
</p>
<div class="example">
<div class="example-title">
<span>
Example
24
</span>
</div>
<pre class="example">
(value).toExponential().replace(/e\+?/,'E')
</pre>
</div>
<p>
<strong>
xsd:double
</strong>
's
value
space
is
defined
by
the
IEEE
double-precision
64-bit
floating
point
type
[
<cite>
<a class="bibref" rel="biblioentry" href="#bib-IEEE-754-1985">
IEEE-754-1985
</a>
</cite>
].
</p>
<div class="note">
<div class="note-title">
<span>
Note
</span>
</div>
<p class="">
When
data
such
as
decimals
need
to
be
normalized,
JSON-LD
authors
should
not
use
values
that
are
going
to
undergo
automatic
conversion.
This
is
due
to
the
lossy
nature
of
<strong>
xsd:double
</strong>
values.
Authors
should
instead
use
the
expanded
object
form
to
set
the
canonical
lexical
form
directly.
</p>
</div>
<div class="note">
<div class="note-title">
<span>
Note
</span>
</div>
<p class="">
When
JSON-native
datatypes,
like
<a class="tref internalDFN" title="number" href="#dfn-number">
number
</a>
s,
are
type
coerced,
lossless
data
round-tripping
can
not
be
guaranted.
Consider
the
following
code
example:
</p>
</div>
<div class="example"><div class="example-title"><span>Example 25</span></div><pre class="example">var myObj1 = {
               &quot;@context&quot;: {
                 &quot;number&quot;: {
                   &quot;@id&quot;: &quot;http://example.com/vocab#number&quot;,
                   <span class="diff">&quot;@type&quot;: &quot;xsd:nonNegativeInteger&quot;</span>
                 }
               },
               &quot;number&quot; : <span class="diff">42</span>
             };
// Convert the JSON-LD document to RDF; this converts 42 to a string
var jsonldText = jsonld.toRDF(myObj1, myRdfTripleCollector);
// Convert the RDF triples back to a JavaScript object
var
myObj2
=
jsonld.fromRDF(myRdfTripleCollector.getTriples());
</pre>
</div>
<p>
At
this
point,
<code>
myObj1
</code>
and
<code>
myObj2
</code>
will
have
different
values
for
the
&quot;number&quot;
property.
<code>
myObj1
</code>
will
have
the
number
<code>
42
</code>,
while
<code>
myObj2
</code>
have
an
object
consisting
of
<code>
@value
</code>
set
to
the
string
<code>
&quot;42&quot;
</code>
and
<code>
@type
</code>
set
to
the
expanded
value
of
<em>
xsd:nonNegativeInteger
</em>.
</p>
<div class="note">
<div class="note-title">
<span>
Note
</span>
</div>
<p class="">
Some
JSON
serializers,
such
as
PHP's
native
implementation
in
some
versions,
backslash-escape
the
forward
slash
character.
For
example,
the
value
<code>
http://example.com/
</code>
would
be
serialized
as
<code>
http:\/\/example.com\/
</code>.
This
is
problematic
as
other
JSON
parsers
might
not
understand
those
escaping
characters.
There
is
no
need
to
backslash-escape
forward
slashes
in
JSON-LD.
To
aid
interoperability
between
JSON-LD
processors,
a
JSON-LD
serializer
<em class="rfc2119" title="must not">
must
not
</em>
backslash-escape
forward
slashes.
</p>
</div>
</div>
<div class="appendix section" id="appendix-a">
<h2>
<span class="secno">
A.
</span>
Initial
Context
</h2>
<div class="issue">
<div class="issue-title">
<span>
Issue
8
</span>
</div>
<p class="">
It
is
<a href="https://github.com/json-ld/json-ld.org/issues/80">
still
being
discussed
</a>
whether
JSON-LD
has
the
notion
of
an
initial
context
or
not.
If
JSON-LD
has
an
initial
context,
it
<em class="rfc2119" title="must">
must
</em>
be
specified
external
to
the
JSON-LD
Syntax
specification
at
a
well-known
location.
</p>
</div>
</div>
<div class="appendix section" id="acknowledgements">
<h2>
<span class="secno">
B.
</span>
Acknowledgements
</h2>
<p>
The
editors
would
like
to
thank
Mark
Birbeck,
who
provided
a
great
deal
of
the
initial
push
behind
the
JSON-LD
work
via
his
work
on
RDFj,
Dave
Lehn
and
Mike
Johnson
who
reviewed,
provided
feedback,
and
performed
several
implementations
of
the
specification,
and
Ian
Davis,
who
created
RDF/JSON.
Thanks
also
to
Nathan
Rixham,
Bradley
P.
Allen,
Kingsley
Idehen,
Glenn
McDonald,
Alexandre
Passant,
Danny
Ayers,
Ted
Thibodeau
Jr.,
Olivier
Grisel,
Josh
Mandel,
Eric
Prud'hommeaux,
David
Wood,
Guus
Schreiber,
Pat
Hayes,
Sandro
Hawke,
and
Richard
Cyganiak
for
their
input
on
the
specification.
</p>
</div>
<div id="references" class="appendix section">
<h2>
<span class="secno">
C.
</span>
References
</h2>
<div id="normative-references" class="section">
<h3>
<span class="secno">
C.1
</span>
Normative
references
</h3>
<dl class="bibliography">
<dt id="bib-BCP47">
[BCP47]
</dt>
<dd>
A.
Phillips;
M.
Davis.
<a href="http://tools.ietf.org/html/bcp47">
<cite>
Tags
for
Identifying
Languages
</cite>
</a>
September
2009.
IETF
Best
Current
Practice.
URL:
<a href="http://tools.ietf.org/html/bcp47">
http://tools.ietf.org/html/bcp47
</a>
</dd>
<dt id="bib-IEEE-754-1985">
[IEEE-754-1985]
</dt>
<dd>
IEEE.
<cite>
IEEE
Standard
for
Binary
Floating-Point
Arithmetic.
</cite>
See
<a href="http://standards.ieee.org/reading/ieee/std_public/description/busarch/754-1985_desc.html">
http://standards.ieee.org/reading/ieee/std_public/description/busarch/754-1985_desc.html
</a>
</dd>
<dt id="bib-JSON-LD">
[JSON-LD]
</dt>
<dd>
<cite>
<a href="http://json-ld.org/spec/ED/json-ld-syntax/20120522/">
The
JSON-LD
Syntax
</a>
</cite>
Manu
Sporny,
Gregg
Kellogg,
Markus
Lanthaler
Editors.
World
Wide
Web
Consortium
(work
in
progress).
22
May
2012.
Editor's
Draft.
This
edition
of
the
JSON-LD
Syntax
specification
is
http://json-ld.org/spec/ED/json-ld-syntax/20120522/.
The
<a href="http://json-ld.org/spec/latest/json-ld-syntax/">
latest
edition
of
the
JSON-LD
Syntax
</a>
is
available
at
http://json-ld.org/spec/latest/json-ld-syntax/
</dd>
<dt id="bib-JSON-POINTER">
[JSON-POINTER]
</dt>
<dd>
<cite>
<a href="http://tools.ietf.org/html/draft-ietf-appsawg-json-pointer-02">
JSON
Pointer
</a>
</cite>
P.
Bryan,
Ed.
IETF
Draft.
URL:
<a href="http://tools.ietf.org/html/draft-ietf-appsawg-json-pointer-02">
http://tools.ietf.org/html/draft-ietf-appsawg-json-pointer-02
</a>
</dd>
<dt id="bib-RDF-CONCEPTS">
[RDF-CONCEPTS]
</dt>
<dd>
<cite>
<a href="http://www.w3.org/TR/2011/WD-rdf11-concepts-20110830/">
RDF
1.1
Concepts
and
Abstract
Syntax
</a>
</cite>
Richard
Cyganiak,
David
Wood,
Editors.
World
Wide
Web
Consortium
(work
in
progress).
30
May
2012.
Editor's
Draft.
This
edition
of
the
JSON-LD
Syntax
specification
is
http://www.w3.org/TR/2011/WD-rdf11-concepts-20110830/.
The
<a href="http://www.w3.org/TR/rdf11-concepts/">
latest
edition
of
the
JSON-LD
Syntax
</a>
is
available
at
http://www.w3.org/TR/rdf11-concepts/
</dd>
<dt id="bib-RDF-SCHEMA">
[RDF-SCHEMA]
</dt>
<dd>
Dan
Brickley;
Ramanathan
V.
Guha.
<a href="http://www.w3.org/TR/2004/REC-rdf-schema-20040210">
<cite>
RDF
Vocabulary
Description
Language
1.0:
RDF
Schema.
</cite>
</a>
10
February
2004.
W3C
Recommendation.
URL:
<a href="http://www.w3.org/TR/2004/REC-rdf-schema-20040210">
http://www.w3.org/TR/2004/REC-rdf-schema-20040210
</a>
</dd>
<dt id="bib-RFC3986">
[RFC3986]
</dt>
<dd>
T.
Berners-Lee;
R.
Fielding;
L.
Masinter.
<a href="http://www.ietf.org/rfc/rfc3986.txt">
<cite>
Uniform
Resource
Identifier
(URI):
Generic
Syntax.
</cite>
</a>
January
2005.
Internet
RFC
3986.
URL:
<a href="http://www.ietf.org/rfc/rfc3986.txt">
http://www.ietf.org/rfc/rfc3986.txt
</a>
</dd>
<dt id="bib-RFC3987">
[RFC3987]
</dt>
<dd>
M.
Dürst;
M.
Suignard.
<a href="http://www.ietf.org/rfc/rfc3987.txt">
<cite>
Internationalized
Resource
Identifiers
(IRIs).
</cite>
</a>
January
2005.
Internet
RFC
3987.
URL:
<a href="http://www.ietf.org/rfc/rfc3987.txt">
http://www.ietf.org/rfc/rfc3987.txt
</a>
</dd>
<dt id="bib-RFC4627">
[RFC4627]
</dt>
<dd>
D.
Crockford.
<a href="http://www.ietf.org/rfc/rfc4627.txt">
<cite>
The
application/json
Media
Type
for
JavaScript
Object
Notation
(JSON)
</cite>
</a>
July
2006.
Internet
RFC
4627.
URL:
<a href="http://www.ietf.org/rfc/rfc4627.txt">
http://www.ietf.org/rfc/rfc4627.txt
</a>
</dd>
<dt id="bib-WEBIDL">
[WEBIDL]
</dt>
<dd>
<cite>
<a href="http://www.w3.org/TR/2012/CR-WebIDL-20120419/">
Web
IDL
</a>
</cite>
Cameron
McCormack,
Editor.
World
Wide
Web
Consortium.
19
April
2012.
Candidate
Recommendataion.
This
edition
of
Web
IDL
is
http://www.w3.org/TR/2012/CR-WebIDL-20120419/.
The
<a href="http://dev.w3.org/2006/webapi/WebIDL/">
latest
edition
of
Web
IDL
</a>
is
available
at
http://dev.w3.org/2006/webapi/WebIDL/
</dd>
<dt id="bib-XMLSCHEMA11-2">
[XMLSCHEMA11-2]
</dt>
<dd>
Henry
S.
Thompson;
et
al.
<a href="http://www.w3.org/TR/2012/REC-xmlschema11-2-20120405/">
<cite>
W3C
XML
Schema
Definition
Language
(XSD)
1.1
Part
2:
Datatypes.
</cite>
</a>
5
April
2012.
W3C
Recommendation
URL:
<a href="http://www.w3.org/TR/2012/REC-xmlschema11-2-20120405/">
http://www.w3.org/TR/2012/REC-xmlschema11-2-20120405/
</a>
</dd>
</dl>
</div>
<div id="informative-references" class="section">
<h3>
<span class="secno">
C.2
</span>
Informative
references
</h3>
<dl class="bibliography">
<dt id="bib-ECMA-262">
[ECMA-262]
</dt>
<dd>
<a href="http://www.ecma-international.org/publications/standards/Ecma-262.htm">
<cite>
ECMAScript
Language
Specification.
</cite>
</a>
December
1999.
URL:
<a href="http://www.ecma-international.org/publications/standards/Ecma-262.htm">
http://www.ecma-international.org/publications/standards/Ecma-262.htm
</a>
</dd>
<dt id="bib-TURTLE-TR">
[TURTLE-TR]
</dt>
<dd>
Eric
Prud'hommeaux,
Gavin
Carothers.
<cite>
<a href="http://www.w3.org/TR/2011/WD-turtle-20110809/">
Turtle:
Terse
RDF
Triple
Language.
</a>
</cite>
09
August
2011.
W3C
Working
Draft.
URL:
<a href="http://www.w3.org/TR/2011/WD-turtle-20110809/">
http://www.w3.org/TR/2011/WD-turtle-20110809/
</a>
</dd>
<dt id="bib-UNICODE">
[UNICODE]
</dt>
<dd>
The
Unicode
Consortium.
<a href="http://www.unicode.org/unicode/standard/versions/enumeratedversions.html">
<cite>
The
Unicode
Standard.
</cite>
</a>
2003.
Defined
by:
The
Unicode
Standard,
Version
4.0
(Boston,
MA,
Addison-Wesley,
ISBN
0-321-18578-1),
as
updated
from
time
to
time
by
the
publication
of
new
versions
URL:
<a href="http://www.unicode.org/unicode/standard/versions/enumeratedversions.html">
http://www.unicode.org/unicode/standard/versions/enumeratedversions.html
</a>
</dd>
</dl>
</div>
</div>
</body>
</html>
